Using special characters might be insecure because they are often used in computer programming languages.
In the C++ programming language ~ is the destructor. It gets called when you destroy (reaching end of scope, or calling delete to a pointer to) the instance of the object. Even worse, it's also called bitwise negation (complement), as in the following contexts/examples:
int a = ~100;
int b = ~a;
Output:
-101
100
Hackers would love it if ~ stood for Bitcoin.
http://stackoverflow.com/questions/5343437/meaning-of-tilde-symbol-in-cInteresting, thanks for the insightful feedback. I must admit I don't entirely understand what you are saying, but I get that the tilde could cause problems since it is used in programming languages.