I've noticed it, and I don't mind it for the most part... but sometimes I'll see someone from my realm and want to actually "try" instead of goof off just in case it helps my reputation on the server. But that's partly because I end up pugging raids, so I want those invites.
Then again, sometimes I just discover people that are really bad on my server and have that "shuuuuunnnnnn themmmmmm" feeling. I'm also a jackass at times so its kinda 50/50 between that feeling and "hm I should help them".
*shrug* It doesn't happen often enough (for me at least) to really see a noticeable difference.