Quoted from GibGirl:

Or another - add WiFi and NFC to machines, and release a free app. You can walk up to any machine, use your app as your first ball sits in the shooter lane, and now the game knows your profile. Your score is uploaded to your phone afterwards, perhaps available on a web site, and initials are auto-entered. Now you can track your scores over time on a specific machine and compare to friends. Operators can keep track remotely of machine use and earnings, and get instant alerts if there's a problem.

Quoted from orangestorm87:

I know its not "real" but Pinball FX2 has a table called Epic Quest, where you level up your hero/adventurer and get new items which are then saved and can be used on future plays.
But I agree, having some sort of card or app that lets a machine know its "you" would work well with Pinball as well.

Quoted from Meatneck:

I will ive away my favorite idea..but if someone does it I want a free machine...
Privacy glass. you could literally hide a lower playfield under a playfield or..have a whiteout..where after x amount of time the entire playfield glass whites out and you have to play blind. re: fog or mist
http://polyvisionglass.com/products/switchable-electric-privacy-glass.html?gclid=Cj0KEQjwgoKqBRDt_IfLr8y1iMUBEiQA8Ua7XQpG0iRx0_f4FS37e0wwoVOr2AbGhINSiNIE_a0A-08aAr__8P8HAQ

Quoted from OLDPINGUY:

I have bunches of ideas, and enjoy this thread, and the brilliant ideas I am reading here.
The one Idea I would love to see, is for say, Stern, to have a suggestions page like this thread on their site, and actually use it for new, fresh, and exciting ideas.
It pains me to see such brilliance die in a thread, when even if just a few ideas would get considered.
As we are hard core fans, I think the pool of minds here, could make a huge difference with a few features adopted.
What have they to lose?