Re: If you're hosting new years eve (guest drinking question)

We host family every NYE but no one walks out drunk.

I think having a key drop is the best way. I imagine it would get awkward.

I would get the number of a few cab companies (free?) and offer to do pick ups in the morning for those needing a ride back to their car.

This is a lot on your plate, being pregnant & running around. Under no circumstances should you offer to drive them home. I don't want you on the road at night either - even stone cold sober.

Re: If you're hosting new years eve (guest drinking question)

Generally everyone who gets wasted at our house has a designtated driver who is sober so I don't worry too much.
I only had one incident in all our years of parties (not just NYE parties) where we had to insist someone sleep in the guest room.
He was BAD and came alone with no DD.
My DH actually hid his keys and gave him clothes to sleep in.
He passed out before he could protest TOO much!