Yes, if it can be done, I have done it before but I always remember the one were I was routing for the wrong team and then found out I had the other team and was a big fat loser.
Probably common occurrence. I mostly bet local, but he records all calls to settle disputes. You can just imagine the headache of someone saying they bet such and such on so and so and the book wrote it down "wrong," or not at all.
At least with online you can always check your action. I have called my local back to reconfirm action. Inadvertantly fading yourself might be the key to success.