Not really. I don't really go into it that way -- why would me liking someone's comic mean that they should check out mine? If I read, comment, or subscribe, I'm not doing those things as a favour to the other person as a fellow creator; I'm doing it because I love their work so much as a reader that I want to do those things.
Aw, geez, I guess I don't like the idea of this as like, the bare minimum of being nice, like how it's presented as "at least do this." I think for a creator to notice that one of their readers also has a comic, and to read through that person's work, is a creator going above and beyond and doing something extremely cool. If they support or comment on that work, that's incredible. I've had it happen before, where a creator I admired checked out my work in return, loved it, and gave it a shout out, and it was an amazing feeling. But most of the time, that isn't going to happen, and I don't think it's a good idea to have that as an expectation! There are a few webcomics I really love, and I comment on them because I know how it feels to get comments, and I want those creators to really be able to feel how much someone out there loves their stuff. But if those cartoonists see me as a reader rather than a fellow creator, that's honestly fine and normal, I think!