It's funny,, it seems that 75% of most IFR courses focuses on hold entries and flying holds.. how many of these does someone have to actually fly for every 1,000 hrs of IFR flying? Maybe a handful? 500 hrs in and I've been yet to given a hold here in SoCal.
Oddly the only "real world" hold Ive ever gotten was during instrument training training in SoCAL... I say real world in quotes because it was a very typical SoCAL VFR weekend so it wasn't like we had to hold but everyone and their mother was out trying to do practice approaches. Got a "real world" hold over OCN for the KOKB VOR-A practice approach. They had us stacked 7 deep at 500 ft intervals from procedure altitude on up to 5500ft. We almost went somewhere else but my instructor decided it'd be good practice to have me actually manage all the different aspects of the hold, from radio comms to altitude transitions while in the hold.
That being said, yeah I'm pretty sure that's the only hold I've been given that I didn't specifically request. In fact most of the time when asking for practice approaches, there seems to be puzzlement from ATC when I want to execute either the pre-approach hold-in-lieu pt or the full missed-approach to hold. Its almost like they aren't aware that holding is part of the currency requirement... though given there is no set requirement for number of holds and most people focus on the approaches (and create their own holds without ATC) I guess its not that common of a request.
As to the Ops question:
The prevailing wisdom in the US is that neither ATC or the FAA generally don't seem to really care how you enter the hold as long as you enter the hold and inform them when established so do what you feel comfortable with. I've heard plenty of pilots call themselves out for using the wrong entry type but have never heard ATC question it. I'm not even sure there is an FAR under which the FAA could take action/violate you specifically for incorrect holding procedures as holding entry descriptions are part of the AIM; even a depicted Procedure Turn barb is considered "advisory" and not regulatory. Of course if something bad happens while operating outside the "advisory" parameters, you're going to have to answer to the FAA why you were operating the way you were and your reasoning may not pass their scrutiny enough to not be considered at fault, though again what exactly you'd be violated for is a little unclear and the conversation with the FAA only happens if something bad happens. The FAA/FAR's primary concern as it relates to holds is that you enter and remain in the "protected area." Secondary to that is all the other FAR's that may apply such as not violating an airspace or other directive (such as a specific procedure be NA).
This broad definition offers all sorts of possible cheats as my CFII once demonstrated... For example, the protected area along an airway is 4NM on either side of the airway... Thus you technically have 4NM of airspace on the non-holding side that is classified as "protected" which we regularly used to cheat the turn for a parallel in a way that made it easier to turn and establish on the inbound course in the hold before reaching the fix and having to turn outbound.
In addition to the flexible FAA view of holding entry, this type of question primarily exists as "checkride trivia." You are unlikely to get a hold from an enroute segment along an airway that involves anything other than a direct or parallel entry and even executing a non-airway hold, the chances that the entry is so on the line as to raise question as to the best entry are incredibly slim. Thus its typically the type of question a DPE asks to see how you would handle something that isn't entirely clear.
Note that the above applies to the FAA and flying within the US only. Operations internationally under both local and ICAO rules are known for being more stringent in their expectation that you enter the hold using the correct method and as described without any "cheats." Just something to consider if you are flying internationally since US pilots have been violated by foreign regulators for "bad procedures" and the FAA may go after your certificate for violating foreign regulations just as they would for violating domestic ones, even in situations where the violation under the foreign regulator is not a violation under the FAA.
My personal response in all cases is to ask for ATC for maneuvering space to whichever side I want/need to establish in the hold using the type of entry I would prefer.
I picked up this "go ahead and ask for it" style from here:
https://code7700.com/course_reversals.htm