I DO use basting spray, and have never had any problems such as those mentioned here. Curious. I've basted up to a 72" square quilt before and of course many smaller than that. I know I don't over spray, because the can lasts so long and doesn't gunk up my machine needles. I've mostly used June Tailor, which tends to stay put MUCH longer than the 505. I don't remember if it was the 505 or another kind, but on the back of the can, it actually stated that it was a temporary adhesive that would only last 3-5 days. My June Tailor has lasted for 5 MONTHS before. At least that's the longest time I've been between spray basting and doing the machine quilting. No affiliation, just one happy customer.
Great thread!