The thread shows we are all individuals and deal with things in our own way, within the basic framework of our airline's SEP.
Trainers at my airline of course expect us to enforce the rules whilst retaining some degree of common sense.
At the end of the day, you can inform a pax twice, maybe three times to go back to their seat.
However, if they are desperate then no amount of shouting or threats of police action are going to stop them. The individual in question may have a compelling need to visit the lav...I'm sure you can use your imagination. In that case, I am not going to physically restrain the pax or arrange for their arrest on arrival.
Just use your common sense guys....
p.s. nivsy ...
I don't want to comment on the crew on your flight, but as a rule footrests should be stowed and crew proactive in ensuring compliance with seatbelt signs