From what I've seen, there are only a handful of people on CS who people are reluctant to disagree with based purely on who they are, and that's usually more because others figure those people are particularly wise on the subject and so are probably right than just 'oh, they're popular so I'd better agree with them'.

You do occasionally see people leaping to agree with the 'famous' people, but really the vast majority are just as prone to getting argued with, yelled at, scolded, etc. as anyone else. XD I can only think of a few well-known people here who I've hardly ever seen argued with in the forums, and two of those are Tess and Nick (though I know they do get argued with a lot by PM). There are almost no well-known people that I've never seen someone complaining about. Basically, it doesn't matter how well-known you are around CS - the 'famous' people usually aren't treated much differently, but a lot of people assume that they are and complain bitterly about being ignored because someone 'famous' posted, that the 'famous' person won something over them just by being popular, that no one wants their art because everyone wants art from someone 'famous' instead, etc. It's probably one of the most common complaints I see, and one of the most unfounded. If an unknown person makes a good point, people are probably going to agree with them, even if a 'famous' person disagrees but makes a poor point. ^^ Also, as Coalchaser said, just because someone is well-known, that doesn't necessarily mean they're respected - they might be well-known for being on every art shop's Banned list. o.O
To bring this around to be mostly on-topic, something that annoys me is people assuming that 'famous' people get preference in the adoption centres. Maybe it's different in other adoption centres - I haven't checked, so I can't say for sure - but in mine at least, I don't even look at the names until the winning form has been determined. If in any doubt about my own objectivity, I bring in another judge who doesn't know any of the people involved just to be sure that I'm not biased, and lots of 'unknowns' have won characters. And yet people still say "You only give characters to famous people!" *headdesk* Ah, c'est la vie. XD