Sally was in one video game called "Sonic Spinball" Here's evidence.

This video proofs that she was canon, so people now suppose to say she was canon instead of not. Don't like Sally in it? Get angry at Sega not Sally Fans. Still don't like her in the comics and TV shows? Can't be angry at Sally fans. Sega made the characters. You don't like Sally? Tell Sega to eliminate Sally in the comic series,etc. Than you might not have to worry about the fans and the characters.