Managers should not be allowed

To talk to referees at half time

This only applies more pressure on referees to give a side a penalty or a favourable decision.

This should be banned and not allowed.

This is well exploited by top managers like Alex fergeson, who today at half time has spoken to the referee.
from bbc

"Sir Alex Ferguson is waiting on the touchline as the players come off. Who is he waiting for? Oh it's referee Michael Oliver, who gets an ear-bashing as they enter the tunnel"