I would not be me if I resisted jumping into this glorious fray. I should point out that there are various degrees of importance with grammar, expression, and speeling errors. Some are just little annoyances for us grammar police. But some, like the misuse of "can't" are far-reaching, indeed.

To say that one "can't" do something is to say that under no circumstances can one do X, period, full stop. HOWEVER, it has come to indicate not only the absolute ability to do X, but ALSO to mean things that one actually "CAN" do, but CHOOSES to not do. One CAN take a longer lunch break; it is POSSIBLE. But one may CHOOSE not to given the possible consequences. You may say "tomato" and I may say "either" but we CHOOSE either way.

Most of the time when I hear someone use the word "can't" it refers to a choice that someone would rather not make. Thus, by using the word, they absolve themselves of responsibility of choosing, even if it is a very unattractive choice with painful consequences.

If you think I am being excessively pedantic about this, look around you, in your personal life and in the bigger world, and just listen to how the word is used and what the difference would be if one more properly indicated permission--I "may not" do it--and choice rather than actual capability.

And yes, language is fluid and dynamic. But there are just some violations up with which I will not put. And speaking of rules...

Saul