I've never had a problem touring a resort as a single person. In fact, I have several weeks that I bought so you'd think that I'd be a good prospect. The person at IOA was sceening people and she must have figured single people would not purchase a timeshare, so exclude them. At least that is the conclusion that I came to. I thought is funny (and stupid on her part).
I've toured HGVC at International Drive - it was pretty low key. I've toured Orange Lake, Vistana, etc. Of the resorts I've toured, Vacation Village at Parkway was the hardest sales pitch that I've been to. As an owner at OLCC, I've been to several tours. Some of the sales people do pitch harder than others so the saleperson and the promotional climate that the resort can make a difference (i.e., Westgate pushes extremely hard according to reports so much so that it is recommended by owners to avoid the resort).