They happen all the time for me at small to medium companies. If the legal team is two people whose desks are by the door, then you are going to eat lunch together at some point. It would be weird not to! Just wait until someone says "anyone want a coffee?" or "who brought lunch?" and then stand up.

Obviously this doesn't happen when the legal team is located three buildings away. At that point you might as well be remote from the perspective of collaboration.