It's kind of obvious when some people do that, but if I suspected someone was doing it I'd pretty much write them off as far as my own being bothered reading their Hubs went. The HP team has access to everyone's stuff. If they want to be bothered checking into any one, individual's, activities they can. I figure that other Hubbers aren't my problem (as long as they don't bother me).
Some people may be better at doing that kind of thing than others, but a lot of people make themselves look really stupid and unprofessional to anyone who recognizes what they're doing. It's up to them if, for some reason, having fake comments on their Hubs works for them. :/
Not everyone with more than one account does "funny business". I have two accounts in names that people wouldn't recognize (although if someone who knows me were to be bothered, he'd probably recognize the writing style that I make no effort to change or hide). I wanted to be able to be freer to write about some subjects than I can be under this account. I'm grown-up and "professional" enough that I disabled comment capsules on Hubs on those accounts simply because I don't want to get into the whole "multiple personalities thing" when interacting with others on this site.
There's so much phony foolishness that goes on on the Internet and on a site like this, I generally avoid anyone that I suspect of engaging in that kind of thing; and I don't take part in any of it myself. Whatever else goes on with what others do is something that HubPages can worry about (or not) and something Google can worry about (or not). :)