First of all, it is simply not a game that I am willing to play.
Secondly, the other team members will know about it (eventually) and will (eventually) try to do the same thing.
Overall, it would be detrimental to team cohesion and would undermine the culture that I want to build:- One that is focused entirely on solving the problem in front of us.
If a member of my team needed a pay rise (i.e. if they were expecting a child) then I would work energetically to represent them within the organisation to make sure that they get what they need -- but for their part I would expect them to interact with me honestly and not play silly games.
Wow, isn't that massively discriminatory? Raises and contributions should be merit- or contribution-based, no more and no less.
Another point is some might feel if they have to ask for a raise, the company has failed them already, they work should have been noticed by then.