I've been guilty of only looking at either General Interest Checks or Advanced, and that's it. I've joined both Casual, Free, and Advanced from doing this, but I haven't really browsed Free or Casual, because those game types don't outright appeal to me. This is perhaps wrong on my part, but that's just what I've felt.
I have no issue with a GM posting in multiple interest checks if it gets them enough willing players to join. However, I feel this can lead to dangerous territory. As others have stated above, someone who browses casual games would expect a casual game to join. IF said GM has also posted in Advanced, then they would get Advanced players interested. I don't think you can have a game that is both Casual and Advanced. Some casual games can have long, elegant posts, and some Advanced games can have short, straight-to-the-point posts, but that's as far as I've seen the two mesh.
There are some who would look at this and be turned off, of course, that's just how it is.
I think one should be cautious and state their intentions outright with what they expect from people. Whether it's posting everyday, posting once and then waiting for others to post first, quality over quantity, or what have you. I think part of this is also worrying about the fact that more often than not, people will leave the RP due to lack of interest. It seems to be a huge game killer, so putting interest out there in a large capacity offers more people to see your game, express interest, and keep it alive. Survival of the fittest, in a way.
But yeah, I have no qualms with it. I've found a few games that did this that I've enjoyed playing in.
