Your game remind me of this idea: https://bitcointalk.org/index.php?topic=521297.0
I like the way that you provide a game dynamics for tipping and incentivize customers in a fun way.

Will the jar owner display the capacity of the jar in advance or is it unknown for the customer what is the remaining amount before it breaks?
Also It may be good that there is a 1st, a 2nd and a 3rd prize provided by the business owner if he/she want to...