It’s not exactly on topic, but I reckon it’s also not entirely wrong in this context:
In my >50 years of making music, i have never, ever, encountered a triple sharp or a triple flat in any music I’ve played. I would welcome the possibility to exclude these theoretical oddities from anything I would compose, arrange or engrave.
On topic: when transcribing older music (renaissance, early baroque), it would be a good thing if double sharps and double flats could be made impossible as well (including E/B sharp and C/F flat). In some music, those just don’t occur (either).
Which brings me to another minor feature request (It has been requested before): a button/menu command/key command to just ‘respell’ a note, without having to calculate whether it’s ‘up’ or ‘down’. (S*** had that; I admit I liked it). Of course, it should skip spellings not pertaining to the music style or period. Which means in most cases you’d need to invoke this function only once per note, to change a sharp to a flat for example, never showing any of those moronic triple-sharps and triple-flats… I’m sorry to hurt anyone’s feelings if you’re fond of them 
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