In response to a story that was relayed to me this week, I will say a word about dessert trays.
Often, restaurants will have a tray prepared with one of each dessert that they carry. It is common to replace perishable items such as ice cream or whipped cream with scoops of butter so the presentation lasts throughout the day. Such was the case in this particular instance.
Apparently, one group of guests thought that the display tray sitting in the corner was free for the taking. So, they took the desserts and ate them, butter and all. According to their server, they never noticed.
For your own safety, please don't eat things hanging around restaurants. There may be far worse things than butter on them.