Thoughts on Crosshairs. Are they unfair?

Hey there,

I've has a few discussions with peoplr on their thoughts about Crosshairs.
The reason I'm bringing this up is due to Multiplayer servers disallowing them for reason like:
"Do not use any unfair advantages including 3rd party software and Crosshairs".

I get the point of it but I do find players and even some Multiplayer Server admins using Crosshair addons.
They always seem to say something along the lines of:
"I thought they were allowed" or "I forgot to disable it".

Personally I do use a Crosshair and I'm not really sure what my opinion is about it.
If someone tells me to disable it I will.
Can't wait for replys!

Thanks,
Nocaob.