I've had a couple close calls with the airspace in SoCal.
The first, I wasn't really in danger of busting but it made me feel like a jerk. I was coming back from my long cross country to Harris Ranch (3O8) for my commercial and was climbing through Avenal (AVE) along V107 in a Grumman Tiger without GPS so I was shooting for close to MEA (11,000') even though I was VFR to ensure I had good navaid. Now 11,000 is about 80% of service ceiling for the Tiger and it certainly isn't fast getting there.
I actually had the Tiger up nearly at its service ceiling of 13,800' earlier in the day thanks to some clouds over the sierra nevadas, in fact I think I worried ATC a bit there too since I was at 10,500 on flight following through the MOA and mountains and was advised to contact Oakland Center when able only to run into a wall of clouds that blocked my path and required a good 10-15 minutes of circling without radio contact to climb the 3000 ft to service ceiling to get above at which point center came in and I could hear them asking for me, but I digress...
So there I was at 11,500' on V107 enroute to Fillmore puttering along in my 145mph Tiger. About 10 miles out of Fillmore I switch over to SoCal to pick up flight following and was hoping for a lower altitude transition through the LAX Bravo only to hear ATC talking to a regional jet about a VFR aircraft off their right side, same altitude and 10 miles out from Fillmore... Im like gee that sounds like me so I quickly jump on the radio and start talking to control. Sure enough it was me and they had been vectoring aircraft around me for the last 20 minutes as I was right on the arrival corridor for the SADDE SEVEN STAR which was in some pretty heavy use thanks to some storms that had rolled through LAX while I was at dinner. I apologized and the controller was very nice about it, he said I wasn't doing anything wrong (which I didnt think I was) and they just didnt know what I was doing, where I was going and I wasn't on freq. I decided I had added enough work load to the controllers enough for one evening and kept my 11,500' altitude above the Bravo until I got to the other side of LAX where I cleared through t
The next closest I've come to busting an airspace was on a night flight to Brown (KSDM) which is 2 NM north of Tijuana airport (MMTJ) on the other side of the US/Mexico Border. It was also my first flight down to the border area so I had asked for in addition to clearance through the Bravo around KSAN, I asked for flight following which I got and was given some headings to fly which I had some difficulty doing thanks to a HSI that unknown to me would get stuck when turning between certain headings resulting in huge DG errors. So I was a bit distracted with diagnosing my heading issue coupled with flying an unexpected course down to the south end of the San Diego bay (I had planned to go direct POGGI VOR once past KSAN) when SoCal advised flight following was cancelled and Brown was to my left and 5 miles. I look out to my left and see what I think is Brown at my 10 o'clock. I made a left turn towards the airport and was flying along in my 130mph Arrow thinking how remarkably straight the line of lights in front of me is... Suddenly my skydiving training kicks in and I remember straightlines dont occur in nature but fences do... What I was looking at was the bright lights of the US side of the border compared to the dark openness on the Mexican side of the border and realized the airport I was headed towards was distinctly on the other side of that divide. I quickly found Brown, now over my left shoulder between my 7 and 8 o'clock and landed without further issue. I was probably a few seconds from entering the ADIZ.
I had North Island Tower once clear me for the Bay tour and was advised to keep offshore and avoid overflight of the docked ships but I dont recall receiving an affirmative clearance into the Bravo surface area over the bay just to the northeast of NZY but considering North Island coordinates the clearance in that area, Im going with I either missed their clearance or they just didnt positively state I was cleared into the Bravo as nobody complained and I didnt get in trouble for it (plus I did exactly what they told me to do).
By far the closest I've come to busting the Bravo was with my CFII on a missed approach out of Montgomery (KMYF). We were on the ILS 28R and had briefed with the controller we would follow the missed approach procedure to MZB radial and return to the North VFR. The missed approach called for a climb to 1100, then a climbing left turn to 3000' via heading 270 to intercept R-326 off MZB out to CARIF.
In the cockpit, we briefed the Bravo floor was at 4800' where we were and it increases as you get further away however, we had gotten a little complacent doing IFR training and having flown the route so frequently at lower altitudes VFR below the Bravo that we forgot to brief the ceiling of the Miramar bravo over the coast and forgot exactly what it was.
The Bravo in that area has a little cut-out for Miramar with a floor of 1800' and a ceiling 3200' with the larger San Diego Bravo having a floor of 6800' and a ceiling of 10000'. So there we were at 3000' on 326 scrambling to pull up the VFR chart and trying to quickly climb to clear the bravo (it was 50/50 whether to dive for the deck or climb for the sky... we guessed the ceiling was less than 4000' as we knew it was a sizeable corridor and that it allowed you to come out below the bravo where we were which was 4800) I dont know if we busted or not but we didnt hear anything. Either we successfully climbed out of it before the bravo, we corrected quickly enough or the controller recognized us flying the missed approach at 3000' because we never heard anything about it.
Particularly with the first 2 scenarios, even though the first one was far from a bust, these were all learning experiences. The 3rd one was almost certainly a miscommunication but the 4th was definitely a reminder not to get complacent in familiar areas and a reminder to be careful with how practice approaches will terminate.