I don't know why I'm attempting to answer this, but I will.
Just filing an IFR flight plan doesn't really do anything, except start the process by which ATC can prepare a clearance for you when you request it. There's no reason for you to file an IFR flight plan if you're not intentionally embarking on an IFR flight (ie, it doesn't help in an emergency situation). But I can't think of any way that just filing the plan could get you in trouble. They don't cross-check that you have an instrument rating or anything like that. Instrument students do this all the time (though will usually put their instructors' names in the remarks as PIC, so there's no confusion later).
It's illegal to accept an IFR clearance if you don't have an IR (or aren't current for instrument flight). If/when you do an instrument rating, you'll figure out how that works, but in short you call up ATC and ask them for a clearance. In the background (and semi-automated) they look up your flight plan, modify it as needed to fit in the system, and give you instructions to get where you're going in the IFR system. Unlike VFR flying, in IFR flying you don't get to just fly around -- you have to go precisely where you're cleared.
If you "know how to fly IFR" (ie maybe you have the rating but aren't current) and get an IFR clearance and fly it appropriately, you're in that world of definitely-illegal-but-very-unlikely-to-be-caught-but-if-anything-happens-it-will-sure-as-hell-be-ruled-your-fault.
If you don't know how to fly IFR (ie probably you, if you're a real person), it will be very obvious to ATC, they will probably be very annoyed at this (because there's really not a way for that to happen accidentally), and will do their best to track you down. Granted, the likely outcome is a suspension, but as much as that doesn't sound so bad, a) they could try to press for worse, as this is pretty egregiously intentional, and b) a suspension will make it hard to get a job flying, or get screened for the DC FRZ, etc. Why would you want one?
Finally, if you're truly worried about the "in an emergency" situation, a) check the weather and don't fly into clouds, and b) if you do unintentionally lose VMC, just call ATC and tell them so. Unlike if you pretend to be IFR, they will be friendly and help you out. And they'll give you instructions (like climbing to altitudes and flying headings) that after your 3 hours of private pilot instrument time you'll have half a chance of following and surviving, unlike instructions (like joining airways and shooting approaches) that you might struggle to complete in a non-emergency situation.
In short:
1. Just filing a flight plan (probably?) isn't even illegal, and almost certainly won't get you in trouble, but also there's no reason for it.
2. Trying to get an IFR clearance when you don't know what you're doing is going to be damn obvious, get you in lots of regulatory trouble, and dangerous if you get into clouds.
3. Trying to get an IFR clearance when you do know how to do it but aren't legal for it is illegal and might possibly get you into regulatory trouble, but it's probably unlikely.
4. If you're VFR-into-IMC emergency, just tell ATC and they'll be able to help you much better than if you somehow pretend you're IFR or something else nonsensical. ATC is almost as unwilling to see you as a hole in the ground as you are.