While I agree with you, the Oxford game is more recent than 6 years and it isn't beyond the realms of possibility that someone - even if not a Dingle themselves - with such an infrequent purchasing record might be buying a couple of tickets to sell to the other lot for a huge profit.
Also, I know of a fair few Dingles who allegedly did go to some Rovers games - not against Burnley - toward the end of the relegation season to gloat (just as I and many other Rovers fans went to t'Turf in the 80s in the hope of seeing them slip out of the football league).
Its a tricky one but I think the club is right to ask a few questions of the very infrequent purchasers.