I am not trying to rectify what happened.
It might be that he sat in one of the extra revenue seats that offer extra legroom. JetBlue does not allow sitting in those seats under any curcumstance. They must be very hard on their cabin crew in forcing them to be tough because I was berated by a crew mwmber for entering the row while I let her pass in the aisle.
I respect anybody’s right to be frum but the only real way to fly under those conditions is to pay for aa extra seat and yes, there is such a possibility.
I have flown quite a bit and rarely is there any restriction on switching seats after boarding has completed. I also believe the weight balance issue is more front to back rather than side to side.