ok, I've never heard the word catless but I've definitely driven vehicles that had a pipe welded in place :)
I or a family member has acquired a few vehicles where the catalytic converter was cut out by thieves, and I've done both so I can tell you from experience that it's the difference between $15 and $800 (parts and labor).
Having grown up extremely poor, sometimes families make those decisions because they don't really have a choice. Thankfully nowadays I do so I tend to err on the side of being a good citizen but personally will not judge anyone who choose s to weld a pipe in place rather than spend the exorbitant amount necessary to replace it, especially considering it might just get stolen again.