I think it´s not illegal, as it has not been looked at, yet.
And I do not remember any contract, I had to sign during my frequent hotel visits, where mining or excessive use of power was prohibited.

If you ask me, there won´t be something like a single counter for each hotelroom. But if power consumpstion rises extremly (and it will ;-) ) there could be someone looking for the reason for that.

That will not happen after one or two days. But I think if you stay for a couple of weeks... it could happen.

I think 1KW should not kill the fuse, nor will it burn your hotel room.

What is your estimation on reward?
Is it worth the effort/risk?

I did some mining with two R9-290X and gained about 40$/month.
Without paying for electricity it was a good deal :-D