1. The hotel was quite generous. a 12Eur bottle is a very nice gesture for what amounts to a minor inconvenience. Remember, a call to the FD by picking up the room phone would have taken less than 5 mins.
2. If this was actually confidential & important work, I would never do that on a public network such as a hotel. Yes, data access can cost money, but it's a pittance if the work is confidential. At a minimum, I would not be online any longer than necessary. In other words, log on, download what you need & go offline. Do your work & create a document to email. Then go online and email it.
3. This isn't just about spies, it's about the fact that you were staying at a business hotel frequented by Americans. Don't think that there aren't a lot of people who wouldn't be interested in the commercial value of your work if it really is confidential & important.