Very wrong, don't try this.
I didn't want to give bad info, so when in doubt do a search. heh Just did a search for about an hour and came up with two posts that say that the pressure can build up to the point of popping something if shutting off an air valve on a DIY.
I didn't find anything that said it was bad or good to do what I did and use an air valve to reduce bubbles, however it is prob better to err on the side of caution and not do what I did. Thanks for bringing that to my attention, Bandit. That's why I like this forum. People help each other- even in corrections.