that's awesome! very respectable and i'm sure karma will hit you back big somehow. good luck with everything, getting your grandma to understand and all. i bet the birthday thing will work and also coming off as informed as possible. maybe even get the set up and show her what it's like with the security and all (lock) and make sure you're able to return it in case she flips out. but yeah a visual demonstration of how sure you are that the rtb won't get out would probably do the trick topped with a bit of that birthday plea.