Some transceivers do have problems with overshoot. They don't want to deal with a lot of tube failures so they give instructions so that maximum safety to the equipment is insured as BlowinSmoke said. Hams are no different than the rest of general population. Some are very smart and some aren't. You have to write manuals for the ones that need it the most. Tuning at max exciter power is not always the best way because you're beating the tubes to death for no good reason. Some HF rigs produce 200 watts, what do those guys do? You have to know your equipment and use good judgement.