Have another similar story using kid to get free middle seat:

Flying out of MCO family of 5 was in ABC DF (trying to keep middle open), pax boarded who had the E boarding pass and saw a stuffed animal buckled into E and was told by the dad in D that she could not sit in E because his son's stuffed animal (son was in window) was going to sit there.

Flight was a 752 and I was in Exit row at door 2, E went to FA standing and told FA what happened and FAs mouth about dropped to the floor, long story short stuffed animals aren't entitled to a seat and guy in D gave up and moved son into E and gave E the window seat.