I haven't had it selected in days, queued for a match, and got Mom. Result: 30 point loss that I didn't choose to risk in the first place. I'm guessing the weekly reset had something to do with it.
In those few days, did you delete your internet files/cookies? http://forums.cardhunter.com/threads/suggestion-save-changed-options-on-account.3607 Currently, various user-set option like the "GM opponents" one are stored in your temporary internet files. As you can see in that thread, some users think this should change to avoid accidental problems.
