We're selling our house at the moment with Open Homes held most Sundays.
Having now experienced it ourselves from the vendors point of view, I feel very different about them. I no longer want to go sticking beaking at other peoples homes just for the sake of it. We've got an offer in on a house with a one of the conditions stating we have to sell this one before we can get going with other conditions.
I find people that just want to waste time viewing properties for the sake of it get the hopes up of the vendors. I'm not sure why you just can't look on realestate and open2view websites to get an idea. That's the way we've done it as we feel it's unfair nosing around just to get an idea of price when we've got no intention of buying.