While I agree that the concept of placing a hit on someone just to kill them with no RP reason is A. Stupid af and B. Just loopholing RDM, I will never support any suggestion which involves punishing players using assumptions as opposed to hard proof, just because someone does the hit in two seconds doesn't mean it wasn't in RP although it may be the most likely situation. I also disagree with adding a timer since in the case where it is RP based and someone happens to be near you then it breaks RP more than fixes it since the hitman has to wait while being able to get an easy kill.
All in all this is a problem however is not something worth fixing and to sum things up:
1. I disagree with warning people based off of assumptions from time logs.
2. You cannot prove whether the hit was valid or not.
3. Adding a timer may ruin RP more than it improves it.