Lots of thing cost $1-2 that you might want to tip for. Bartending during drink specials, valet, coat check, bag check, bell hop, etc.

In defense of this, I work on a service that uses square and allows tips. One of the issues with square tips is you can only ask for percentages, not dollar amounts. Since the service I work on usually costs $1-2, we have to put in high percentages for tips in order for it to be meaningful. I believe ours is set to 25, 50, 75 and 100%. Which is usually equivalent to <$2. They could have had a similar situation here except whatever service they offer ended up being far higher than normal.