This is also a trend I have been seeing on snapchat. Quite a few people I follow who are either servers or a server as a second job have been posting on their stories that are way down. People keep stiffing them because they are angry over masks or that they were told no when they wanted to sit at a particular table or booth, but were told no because of social distancing measures. Only every other booth can be filled. People don't like to be told no or what to do. And they are taking out their frustrations with their tips.
For example, yesterday from in Florida someone's lunch came to $28. They paid with a $50 bill. Left no tip. This person also had chewed the servers ear off about having to wear a mask to get into the place and be seated.
To make matters worse, because of lower capacities in restaurants, many have initiated tip pooling and including the bus staff in the pool. With tips being a substantial portion of their wages they can't make a living off of this. At least 2 servers I follow who are in their late 20's had to move back in with their parents because they can't afford rent. Their restaurant never closed and they were never laid off or eligible for unemployment. They have just seen a drastic reduction in trips.