[Multiplayer] Control Time Dilation on Player

Hi everyone

I want to slow specific player via CustomTimeDilation

I have variable:
q1

Variable replicated for everyone.

Also i change it only via this function:
q2

So when variable changed, OnRep called and all players set CustomTimeDilation for this player.
Everything works fine, but…

If variable not replicated for players, server not corrects player movement. Should i expect that?

That means if player for some reason(cheating) wont change his CustomTimeDilation when OnRep called, he will move/jump/attack/etc with same speed. Like CustomTimeDilation = 1.0f.

So… How to check on server if player not cheating and his CustomTimeDilation is good?

Thanks for help