"Pull this on you"? You sound like a real joy to work for.
This is expressly why I choose gigs where I'm working directly for an owner if at all possible. If you've created value, owners know how important you are and will take your request seriously as long as it's reasonable.
In my career, I have received 100% of the raises I've requested ... at least a half dozen times. I've never once received a no or even negative push back. Owners were eager to retain me.
Even if your intention as a "line manager" is to not give the raise, the right move is to at least feign consideration for a few days and show the employee his request at least matters enough to think about.
Letting everyone know they'll immediately be shown the door if they dare request an increase would create a terrible culture. Clueless management.