Can you not?

I've written before about negation and the difference in meaning when it takes different scope. The other day, a friend in the pub said this, directed at a football 'pundit' on telly:

You're 60, can you not wear a suit and trainers? 

By this, he meant

Because you're 60 [and should know better/are too old], please don't wear a suit and trainers. 

It can have another meaning, though, and one that I think is much more accessible, or perhaps only available, in certain dialects:

You're 60, so is it impossible for you to wear a suit and trainers?

For me, both those readings work fine for the sentence and the intonation is pretty much the same in each case. The difference is once again a matter of how 'high' the negation is in the sentence:

Is it the case that
you can
[not wear a suit and trainers]?

vs

Is it not the case that
you can
[wear a suit and trainers]?

For more on this, a very easy to read article (old now, but still good) is Bob Ladd's 1981 paper.