The problem comes when the Kop is a sell out or very close to a sell out, like it's been several times this season.
It will be like playing musical chairs, you go to the toilet for a leak, then when you come back your seats gone.
Also imagine not being able to find any empty seats anyway, there would be quite a lot of people going to stewards asking them where the empty seats are.
Also how are seats allocated to season tickets identified or aren't they allowed their chosen seat? It would put loads off from renewing their season tickets.
Then if ST holders are allowed their seats how is that identified and what happens if the season ticket holder fails to attend, can someone else sit in his seat.
What if the season ticket holder is stuck in traffic and arrives 20 minutes into the match, to find someone else sat in his seat.
It would be a total nightmare.