Good Form?

We had a group of 6 come into the cafe today and they brought decorations, a cake and their own liquid refreshment with them.  This was in the middle of lunch.  They requested we provide them with fancy glasses, they requested we refrigerate their cake while they had their lunch, they requested we provide them with plates, a knife to cut the cake, a spatula for serving and utensils for eating, they put up their own flowers, put some huge centerpiece on the table, dropped a ton of confetti hearts all over the table and enjoyed themselves a little valentines day lunch.  I don't know what planet people live on when they think it is okay to go to a place of business and throw yourself a party with your own stuff right in the middle of their lunch hour.  Who brings their own dessert, drinks and decorations to a sit down restaurant?  Am I out of line here, is this actually good form, approved by the masses?  Is it okay to do this to a place of business?  Well, they bought sandwiches so I guess it is okay, I mean, who wants to pay for the dessert we provide or buy our fountain drinks?  I understand people are all for saving a buck or wanting to do something special but I think it should be cleared with the owners of the establishment and not just assumed that it is okay to do something like this. It just seems a little weird to me, a bit inconsiderate.  Maybe I'm just bitter because they didn't share any of their cake with me and I had to clean up all their freaking confetti hearts plus I'll be celebrating the valentines day alone once again this year.  Oh, poor me.  Look, the short of it is this; we served them, we were nice, we met their every need but I don't think it is good form to show up at a food establishment with your own grub.