I like your idea but before voting, I have one slight confusion that needs some attention. What if presi camps at police spawn along with secs. Suppose cops and all sec dies, they will respawn at opposite spawn (security spawn as you said above). It will take time for them to reach presi, right? Till then, what about presi who is left all alone in that terror's hell? He will instanly die, not even a slightest chance of survival. In this case, terror team will prove OP over presi.
My solution is to simply respawn securities and police in the opposite spawn from where the president is camping. For example, if president is camping at police spawn, police and security respawn at security spawn. If he is camping at his own spawn, police and security respawn at police spawn. If he is not camping at a spawn, everything would be as usual.
On the basis of my observation I explained, this will make things even worse. Instead, I would like to suggest temporarily removing security armour in police spawn zone only. As we know that security were given full armour in latest updates, that armour and sawn off make things worse for terrors. As we know that sawns can't be removed so I am thinking on their armour.
Simple solution: If presi enters police spawn, the security will temporarily loose all of their armour and they wont get it back until presi leaves police spawn. Police will normally spawn from their own zone but their spawn protection should be disabled only in the case when presi is camping in the police spawn. Once security armour is temporarily removed, they wont be able to refill armour except for health from any of the refilling point. This will make things even for both sides, terrors as well as presi and his team.
I still need answer of my question tho so I will be waiting for it.