I think that you have something there, Dave. There has been much over-reaction, although I admit that I could have taken more time to explain this area. I just did not think it to be such a huge issue as made out by a few.
It is not as if I - and many others - have not built mitred boxes or enclosures without reinforcing the mitres. Here are just a few of those I have done in the past. No dovetails, no biscuits (splines), no dominos ….
I have used this pencil box every day for the past 12 years …
I was reminded in another member’s post today of this box made for the Veritas Combination Plane. It has been bumped around for 5 years …
I lug this tool box to demonstrations. I am not especially gentle with it …
And more recently I built a new plinth and isolation table for a turntable. The isolation table has compound mitres …
Now it is important to emphasise that I am not recommending that one use un-reinforced mitres indiscriminately; assess the demands and the determine the risk. For example, a small box may have thin sides and thin mitres, but there is relatively less chance of the panels flexing.
Regards from Perth
Derek