I would hate to be the person in 1B. 23 seems excessive for a 2hr flight. If its really a 2hr flight time and you cut 30min for seatbelt on time, thats every 4min. The FA should have said something when they were blocking the aisle. Where was the FA the whole time? Was this one of those FA's that does the initial drink + snack then sits down and reads a book for the rest of the flight? A good FA is almost constantly checking on drinks, etc so I would think the FA would constantly be tripping over the kids and eventually say something out of convenience for his/her self.

I think once you get over one visit per 2.5hrs of flight , it is becoming excessive. Behavior and length of visit counts too. If someone is using the F lav (because the cart is blocking the aisle and quickly exchanging a book or something, I wouldn't count that as a visit. If the two are sharing the same seat, then that's excessive.