Didn't they increase the use of the picknick table's some time ago?
If i had my way, i wouldn't ask to have guests use the tables more often, instead i would request them to be used longer.
I think the guests leave quite a bit too fast considering they should be having a drink or having dinner.
Back on topic though. Make sure you have some shops nearby as guests with food/drinks often like to sit down. And as suggested above, try removing some other benches that are nearby.