Nope, I think to judge by gameplay (and some serverside and clientside scripts). But not by fact of *.dll using.
Prevention is better than the cure. Saying that everyone is free to load any .dll's is just asking for trouble. You're too naive if you think it won't be abused.
Player's PC/game's memory is not under your control.
Where do you think client scripts are stored? They're stored in each client's PC memory, guess what, every time you create a variable in a client script, it's stored in the clients' memory, you're manipulating the client's memory, you're controlling it in a safe environment.
So editing of game's files is authorized? Devs not protected it. Try to think yourself to draw the border of *cheating* instead bringing authority of vc-mp devs and their actions of .asi or anything else.
I'm not saying that the only things which devs protect are the the only ones that shouldn't be allowed, it was simply another reason to demostrate that letting players load whatever .dll's they want to is a bad idea.