That Family Guy ruling was just handled incorrectly.
I can get with MHS on clarifying some verbiage that a stuck ball is a stuck ball whether in single ball play or multiball play, and that stuck needs to be dealt with IMMEDIATELY (using the same rules).
Allowing a player to shoot another ball is not acceptable if you can safely trap up and go in and get the ball. This actually came up at IFPA12 with Jorian on Star Trek. He had 3 balls trapped on the left flipper with a ball stuck in the jets. He asked if he could shoot the orbit with one of the balls so he could maintain control of the others, and we improperly allowed him to do that. The only solution should have been, you can try and shake it out yourself, or we will free it, but that will result in all your balls draining and being re-kicked back into play (i.e. he loses his controlled situation).
Obviously things get more messy if you’re playing a game that you don’t have the keys to get into . . . what if the interlocks aren’t disabled (now you’re telling the player to shoot it anywhere connected to a high voltage coil - kickout hole, etc).