Spelling PROST -- I was shooting the game before Ferret was, and I commented early on that PROST was harder to spell than you would think, and we might need a stein, which he found difficult to believe, given they are right there, but they just seem hard to collect unless you are really focused on them. So we did discuss a stein for it, but decided against it, since the default behavior is to have lock lit at start of game. I will say there is nothing more annoying that making the ramp shot and not getting the lock. So, if you own the game, you may want to change the difficulty setting for Beer Barrel Locks (medium/default gives you one lit lock, Easy will give you 2)
Also, set 'Release Beer Barrel Locks at end of Game' to 'OFF', which I am guessing is what was meant by "I'll play until I get it", since the game allows lock stealing (beer barrel only, not corkscrew) between players and games. You lock the third ball, you get the MB.
MagNab -- inlanes activate MagNabs for you at TAP lanes or upper flipper based on what is going on in the game. The MagNab lamps will be GREEN when the game is going to auto-grab for you. Based on speeds and other factors, sometimes the grab will be missed. If lamps are YELLOW, they you have control of the magnets via MagNabs, if the light is OFF, either you are out of magNabs (shoot newton/captive ball or right ramp, which ever is lit, to collect more) or for game reasons we have it disabled (pretty rare). MagNab lamps flash RED, when the magnets are active.
There is also an auto-grab that is earned via the pops, and that is triggered if the ball exits the pops to the upper flipper. This will trigger the 'Super High Striker', where hitting the newton ball (and then the captive ball into the stand-up target) will award big points. You know it is super striker when you hear Inga count you down in German. We have improved the animation, voice calls, and light shows around the High Striker in the next release.
I can hit the lock pretty regularly, both off the MagNab, on the fly or just when the ball finds it way there (and I am not a great player by any means). Of course I play a lot of Okto, and very little of anything else, so that helps me stay locked in on the spot on the flipper. Once you find the spot, you start to make it with increasing frequency. As Ferret said, making the power too high can make it harder to hit. The annoyance of making the ramp and not getting the lock, as I mentioned above, is pretty high for me, since I do make that shot regularly but I often forget to go re-light the lock, and it seems I tend to immediately make the ramp again, without it being lit. Of course the second most annoying thing is the way too high percentage of the time that when I do start BBMB, that I have no tent mode running.