Definition 1 of 1
The rules fall outside the purview of business lunches or dinners or situations that are pre-defined as treats-owed. The rules are meant to help determine the outcome of open ended social engagements, where there will always be a fight for the bill, but the end result likely follows the pattern I am about to describe.
Here's the basic outline, prefaced with the disclaimer that the subject is a soft science and you are counseled to employ your social skills over your studied knowledge:
1) If you are a grandparent and/or retired and there is anyone in the group past the age of brahmachari (approx. 25), you are excluded from play. You may equalize the debt during diwali by slipping the youngin an envelop with Rs. 100 and a 1 rupee coin.
2) If it's a mixed age group, all gainfully employed, with a sprinkling of filial relationships present, and only one clear elder, the elder pays. Case closed. Don't argue, don't bother reaching.
3) If it's a group of young (usually unmarried) peers, and no other family is present, it's the first one with the rich parents to reach for the wallet, kudos is given, but there will be little resistance. If no one has rich parents, you go dutch. Unless you recently lost a pepsi bet.
4) Needless to say if you are below the age of employment and there is anyone present who is either having job or well settled, you don't pay, they do.
5) If you are a visitor or guest in town, do not do the locals the disservice of attempting to pay. We will come to your place of residence (preferably in Switzerland) when you least expect it and believe me you will show us a good time!
6) The real battles arise in mixed family groups with two or more parental generations and their progeny present. The children look on in glee as the heads of the household duke it out for the "Right of Pay". The rules are lax around who should win, but the more vocal you can be, and the greater the believability of your injured expression, the more likely you will be to tally up the nights total with a ball-point pen in your ruled account book at the end of the month.
The secret play: If one knows it is going to be an open ended social situation and the Right of Pay is ambiguous, the shrewd participant will slip the payment by way of HSBC credit card to the restaurant staff on the sly, ahead of time, so that when the inevitable fight ensues, the battle is already won.
Other Mom: (signing payment receipt already)
Dad: "What?!! Why?!! Wait!! No!!!!"
Other Dad: "Dooooon't worry"
Mom: "But last time...."
Other Mom: (finished signing, gets up to leave, in sotto voce) "Right of Pay"