[pishpash]

And what would you do if there was a difference?

[s_gourichon]

Return an error code. Also, since the DNS protocol allows ancillary informations, perhaps return additional informations in fields that would seem fit, else in comments.

Edit: this is not DNS over wikipedia. As other pointed out, there is no DNS involved in the linked artifact. One option would be to show alternatives with dates and let user choose.