So a bit more than a witness, but not quite a co-signer? !
I wonder if this was more likely in a parish on the level of Old Machar, though the OPR doesn't say what church they were married in or by what minister. I haven't come across this in any of the other OPR's that I've looked at and that must be several hundred by now.
George Jaffray, the Elder who was cautioner in this case appears in about half of the entries on the page and James Christie, Elder appears in the other half.
Something else to ponder!
Thanks, Andrew for the information.
Looking for: Clerihew, Longmuir/Longmore, Chalmers, Milne, Barclay in Newhills,
Munro, Cadenhead, Raitt, Ririe/Reary