...The point here IMHO is not simultaing reality, is the fact that in game terms either you give Influence skills the same "power" of all the other skills, allowing them to have some impact in the game, or there's no sense in having them.
Agreed.
Although in our games we let the PC make a RR (or appropriate skill check) and if he fails, then he is affected- be it skill or spell. Even if another PC is doing the casting (influencing). Everybody understands the why's and wherefore's so there is no arguing, but payback is a... well, you know
Although my players run a little low on the "role-playing" meter, they do make use of social skills, and usually quite cleverly...