Idea discussion: online booking bots

My idea is to build a site that allows you to automatically book restaurants/gyms/concerts/etc at particular times or when availability opens.

I got the idea from a friend who could never get a spot in her gym class. For a particular class all the available spots were snapped up at midnight when the class became visible. I've written a bot for her so now it books the class automatically and she is guaranteed a spot. She'd be willing to pay a percentage of the booking fee to a service that does this. Are there more people like her is the question.

I wonder how many people would use this kind of service. Does anyone here experience the same problem? Anyone have any suggestions on finding such people?

I definitely don't want to be in ticket scalping. I see this service as different, since it is still the end-customer who buys the spot, they just use a tool to automate it. And I wouldn't allow massive bulk purchases.

I worry this service doesn't scale well since each place would need a custom integration. But at the same time I read you should do things that don't scale.

My bigger worry is that this won't be used by many people, or there are a few popular places that would try and block automated bookings.

Thoughts?