When my children were infants, we frequently booked the "3 class sold as 2 class" 767s between ORD and LAX/SFO. We generally choose 11ABDG for the four of us, with one of the kids in a car seat in 11A and the other in 11D (center section).

After a couple dozen flights with these seats an eagle-eyed FA decided to enforce the obscure rule that (in her opinion) requires all infant seats be placed in a window seat.

Since nobody on this flight wanted to give up an AB or HJ combo in Business for me and my daughter, the FA began scouring the last couple rows of the plane to move us. At that point, another FA intervened on my behalf and called off the forced move. What an angel.

Besides, even if the rule really prohibits car seats in DG middle seats - it's not as though it really placed anyone in harm's way. The car seat impeded no one's progress all thru the flight - the aisle remained clear.