lorax - 10:48 am on Jun 9, 2010 (gmt 0)
A domain registrar I've purchased many domains through used to have this in place. It didn't stop me. The extra step was slightly annoying but I like the provider and their service and I know they're just trying to protect themselves (and me to some degree) so I've completed many purchases anyhow.
I would still complete the purchase at other sites too.