General

I mean, if you're leaving from the building, why not just grab the keys on your way down?

@mattman2623 Yeah you can. They have your card on file and housekeeping comes in to verify that you've left. It just makes it harder to dispute misc. charges since you won't be there in-person

I would just return the key card directly at the front desk in case they start wondering why you haven't checked out yet. They most likely won't ask you anything else, except maybe asking how your stay was after taking the key card. As long as they are aware that you've checked out, I don't really think they care much about the key cards, or who returns them. I mean, I've accidentally left with one several times (returned at least one to them, had three to begin with) when staying at a hotel/hostel.

You need to go to the front desk and check out

What are you asking exactly?

Are you saying like leaving the hotel and no paying or something I'm confused. Unless most hotels actually you pay first hahaha I'm dumb. But really it's not a pain to go to the front and check out.

What's that? Not satisfied with our service? No problem! Have a nice day ********!

almost all modern hotels have the function where you can just check out from your room.
i'm assuming you're scared that since you're not the room account holder, that there will be repercussions. there won't be. they don't care.
if you don't check out, they'll likely call you and ask what's up. depending on the hotel, they might charge you for late check out on top of that, too.

i cant really think of a reason why you would do that lol

Different hotels want you to do different things; I'd ask the front desk.

i wouldn't recommend it