I've seen lots of bands waste time waiting for labels to find them. I think you are doing the right thing in trying to meet them to make contact, but I would recommend a couple of things:

Get with the schmooz crowd. Great getting contacts at expos, but you need to get invited to industry events, launches and parties. that's where a lot of initial business is done. Best way to get invites is to become part of their social crowd. that means getting to know them, most likely through the gigs of other bands. so target the top bands in the area and get to know them and their managers. that way, you are hanging out with them when the label guys arrive and, importantly, they will introduce you to each other. this is perhaps the most valuable part in the whole process.

another good way to get to know the top bands in your area is find out where the big bands rehearse, and when. then start booking yourself in at those times. you'd be amazed how many label employees and top musicians/artists will turn up at the best rehearsal studio in the area. same deal with the best recording studios.

once you are in the schmooz crowd you will naturally be invited to new parties, launches and other events. you get guest list tickets too. you will be amazed at just how many opportunities will be opened up to you, and possibly more valuable, insider industry information such as terms of recent deals, who is looking for what etc.

So, go to gigs, pick the top rehearsal studio, and top recording studio. remember, the people who run the last two also have contacts and if you get to know them, not only will you get first consideration for top rehearsal spots, special rates, favors etc, but you'll get introduced to other bands and a&r men occasionally and get yet again some insider info.

good luck