Of course, the only reason this works is that it is not socially acceptable to break the chain in this circumstance. For instance, if there was a tip/charity ja

Of course, the only reason this works is that it is not socially acceptable to break the chain in this circumstance. For instance, if there was a tip/charity jar (and I'm guessing there isn't in the cases this works) I would simply put my surplus into the tip jar and break the chain, because I find this idea annoying. If there is no tip jar, I would have no choice but to continue the chain.