the only people that made me take of my shoes were people with nice homes(indian, mexican, americans etc etc.)!!!!
if you got a nice brand new carpet it's understandable, because replacing carpet isn't cheap.
If your carpet has been installed for well over 7 years and you still acting like it was installed yesterday....that's a whole different story. I always had to take of my shoes at my girls' house because my father in law is a straight up prick. I always heard it from my lady, "you forgot to take of your shoes, you know how my dad gets"....my response, "fuck what he said, he treats his carpet like if it were made out of gold and shit". THe dude was a neat freak so that explained why he was so anal about his carpet, his lawn, the kitchen, his frige, the couches, the coffe and dinner table(gotta use the fuckin coasters!) etc.
As for my own pad, i like to take off my shoes because it feels comfortable just walking around in my socks(even though the sole doesn't stay white for long) When people come over(friends or family) i don't say shit, because A.it's just fuckin carpet and B. i'm renting.