Here is an obtrusive campaign for SOS Fauna in Sao Paulo for wildlife nonprofit SOS Fauna. They stopped the elevator and recorded the reactions of people as they were "caged up" in the lift. They didn't say how long they were stuck in the elevator, but people were in there long enough to be uncomfortable. *Except for that one couple who seemed like they were happy with the extra snuggle time.
When people were finally "released from captivity" they were given postcards about SOS Fauna's causes. So people in the elevator come to the realization that this was just an elaborate prank. They've been punked for some cause?
Most out-of-home media is fairly unobtrusive, but this one crosses the line when it comes to inconveniencing people. Sure it may have been only a minute or two, but we have no idea what kind of day the people in the elevator is having, and it seemed like one person was on the verge of hyperventilating. What if someone was taking the elevator to rush to the hospital and you stop their dire situation to promote your cause? It just seems disruptive and not in a good way. Pissing off potential supporters seems like a bad start.