People don't dive enough. So they buy all sorts of new stuff for their big new drift dive vacation. In some cases they've literally not been underwater with it for even 20 minutes. Also makes it harder to do an at a glance x-check for folks if you don't know their gear. And some gear harder to deal with (ie, adding weights underwater) if someone turns out underweighted.
My own feeling - unless someone is current with their equip or has current diving - start with a hard bottom dive at 40'.
