Similar thing on Midway (a.k.a. Pacman) doors. Midway added an "anti-penny flipping" device to the coin mech mounting bracket (a.k.a. 'saddle').
Even this trick Midway found a way to fix it ? I use to do this in Pacman/Ms.Pacman in a Bowling alley. I got so good at it and it only takes me one try and BINGO one credit

. But then later on, it feels like the coin mech was very loose and I could not get any penny in, I decided to go with the QUARTER on a String trick and BINGO, it went right in and got myself 99 credits in w/one coin

I guess this is when they found the fix for Anti Stringing device, which they installed a CUTTER so when you pull up the string it gets cut

. Oh well those were the days....Now I just open up the Coin Door and push the coin switch to get credits
