Datapoint -- So I had another fail at using OV MCs, to purchase MO at a third grocery store chain that has worked perfectly w/ OVs in the past. So now I'm like a junkie with a contaminated stash (2x $500 cards). My plan is to liquidate ASAP, probably to fund Amazon gift account and write off the opportunity cost.

Will be interesting to see if other stores are hard-coding against OV like WM, or if this is one-off experience.