It's mainly up to the person in charge of the cannery. Back at Y2K people were coming in repeatedly, buying tons of stuff and then reselling it. This caused tax issues for the church and so they put the one-time-only clause in for non-members. The lady in charge of the Houston cannery seemed pretty mellow on this rule, basically if she liked you you could come back. She mentioned one non-member that had been back many times and was even allowed to borrow equipment to can stuff at home.

-Blast