I don't envy you, Art. I think it would be the right thing to do, to send a replacement, all things being equal. If the first replacement doesn't show up, then the recipient is definitely SOL. I don't know if I'd make it mandatory though - if the print exchange theme is "oversized prints" or "labor-intensive alt-processes", where it could take multiple days and/or cost a small fortune to reprint and remail, then I wouldn't make it mandatory. If you set a rule that all print exchange prints must be smaller than 11x14, then the replacement cost and mailing cost would not be as steep, and you could mandate 1st replacements.