That's about half the tip at the cheap restaurants I go to, so I assume it would be a quarter of the tip at the "good" places.
Now, as I recall the help gets, on average, half their income from their tips.
So, yeah, that's a nice income indeed and you might see why a few folks aren't happy...
``One independent study estimates that OpenTable’s fees (comprised of startup fees, fixed monthly fees, and per-person reservation fees) translate to a cost of approximately $10.40 for each “incremental” 4-top booked through OpenTable.com. To put that in perspective, consider that the average profit margin, before taxes, for a U.S. restaurant is roughly 5%. This means that a table of 4 spending $200 on dinner would generate a $10 profit. In this example, all of that profit would then go to OpenTable fees for having delivered the reservation, leaving the restaurant with nothing other than the hope that that customer would come back (and hopefully book by telephone the next time).''