It had to do with the Mossad being very active in Panama, because of the critical importance of the Canal, so that if American military personnel wandered about in Panama, they might be picked up and interrogated by the Mossad.
I would point out that we might not mind that, because we think Israelis are pretty darn cute ... but it would look bad when we got back to the boat smelling of falafel ...
LOL!
I’d worry more about the Chinese toll keepers at the canal instead.