Not sure about 100gig, but hotels charge crazy amounts of money for Internet entrance. They like provide it themselves, but if you insist on running your own they will happily charge you to give you access to the various parts of the hotel you'll need to make it happen.
I haven't been involved in the last decade, but I'm kind of known as "the guy that makes PyCon networking work", and it can easily be $5K to $10K (from memory) for the hotel, even if you are providing all your own connectivity and gear. I haven't had to do it in recent years because venue Internet has gotten much, much better.
How much does it cost to get a 100+ gigabit link set up for a 4 day long event?