Data point:

I (almost) always buy one VR card at a time. Sometimes I'm asked to flash my ID, which I have no problem doing - some say it may violate their merchant agreement with Visa, I couldn't care less about that - Home Depot asks to see ID when buying anything over $50 with a credit card, I don't mind showing my ID when buying cash with a credit card. No big deal.

Only once have I bought more than a single VR at a time: on the last night of OD selling VRs (I did not know OD would pull the plug 24 hours later, it just worked out that way). I bought two that night (for the full $500 each, so the total was $1000 plus 2 x $3.95, so the total was over $1000). I got a treatment similar to abernard's: manager was called over, got dirty looks from the manager, they photocopied my drivers license, manager made two phone calls (one was clearly to check that the card was valid, the other I don't know), they either looked up or recorded something about me in an online system from one of their terminals). It took about 5-10 minutes.

At the same OD, I bought one VR the following day, and had no hassles, no questions, all was smooth, the transaction took 30 seconds.

It may be that buying multiple cards, or buying cards totaling over $1000, may have triggered the extra scrutiny. Or maybe it was just the crabby manager that day. Or maybe it was sun spots. Who knows. I do know that I've never been hassled like that when I've only been buying one at a time.

Buying the whole rack seems to be just asking for extra scrutiny, and I see no reason to ask for all the consequences that going all-in can easily bring. Hogs get slaughtered, etc.