People tuning amplifiers ip my opinion are the worst culprits. I reckon that a limited range tuner, such as the one inside the 7300 would be tuning at a fairly low output level to begin with. Then if the SWR was above 3:1, I would imagine it would give up rather quickly giving you a High SWR message, or something like that. If the SWR was well within its specified range, it would probably find a match sooner. Forgive me as I never had a 7300, and I could be wrong, but I have had similar rigs with internal tuners, and that's how they played. The guy with the tube amp who tunes for maximum smoke for a whole minute or longer spinning his electric meter like a top, is a far more likely cause of QRM. Don't get me wrong, it's inconsiderate to tune up on anyone who is transmitting. There's just worse degrees of it.