Not blaming Pat's. But I suppose I was thinking about it happening at the turnstiles (pretty sure some club has done this in the recent past); sending them out to the club is a bit more awkward.
If you simply cross out "Adult" and write "Student" on the ticket, on the basis that people are going to get checked going into the ground anyway and anyone with the wrong ticket will be caught, can that system be messed around with? I assume there has to be some check like this anyway otherwise anyone would try their arm and buy a student ticket from Pat's.