I don't get your point. Integer numbers have a finite valid range, and if you don't ensure that your program works only in this range, you are wrong. Whatever the compiler may do, it can't correct your error.
I guess it helps to give some context: unsigned integer overflow is defined. Some algorithms even exploit this behaviour to allow for simpler code.
But even making sure that you stay within the valid range of your integer isn't necessarily enough; you need to check that you're still within the range without going outside of it.
