Actually it is not bad business. It requires an extra lane. Lane that could be used to make more money than on 1 kid.
Plus--the celebration would be "off"--b/c this extra lane is separated by virtue of not sharing the ball return.
Bowling alleys do not seem to have a problem booking these events with this policy.
To those who say that the money shouldn't be a big deal--I offer you the opportunity to offer the OP the cash to make it happen.



