While it's not a slot machine...when I was in college I made a copy to the master key for all the schools pinball machines rear door....that gave me ton of free games...no access to the quarters.

I must admit that I got very good at pinball since I used to play 15 free games at a time between classes

Guess slot and poker machine keys are harder to come by

NOwadays, its very hard if not impossible to cheat the machines from the outside... I remember when people used to string quarters and fish credits then cash out buckets of quarters... there were also strobe light like devices that were being sold for thousands that cost 5 bucks to make... As far as sitting and pretending to play wont work either... the best way to get the drinks is to tip the waitress more than the average player tokes (0.50 -1.00) and she'll start bringing drinks.... tip bigger and you can ask for doubles... I also wanted to add to scams involving coins, You can still scam newspaper boxes if not bolted to the ground, just throw in change, then flip the box upside down and watch the quarters come out... if it is bolted, then you need to do some coathanger fishing <----- Although the coat hanger thing only works in Canada... that's how I was able to buy a mickey in high school every weekend...