Guests Behaving Badly (GBB) is an Australia-only customer blacklist that hotels there can use to weed out potentially bad guests. From their FAQ:
There are a total of five categories of behaviour which include at the lower level blatant disregard for applicable terms and conditions such as smoking in non-smoking areas, using facilities such as swimming pools tennis courts out of hours etc, all the way to non payment of tariff, assault, stealing etc. Persons in breach of the minor conditions referred to would not be reported unless they failed to heed several warnings regarding their activities.
The company has integrated the database into an Australian hotel booking website, Ubid4rooms.com, so that hotels can check for problem guests at the time of booking.