> Takeaway.com and others add a clause in their contract against putting such business cards in their order?
Possibly, buried in the fine print somewhere, but enforced by whom? Aside from the restaurants, only the drivers will see the food. Will they be ratting out the restaurants to their corporate overlords? I doubt it.
They can hire delivery-driver-equivalents of mystery shoppers - better paid workers whose primary job is spot-checking ToS compliance. Or they'll just pay someone to order random stuff from random restaurants and report what they get, under guise of quality assurance.
It's how trust-based arrangements are handled in other industries.
Possibly, buried in the fine print somewhere, but enforced by whom? Aside from the restaurants, only the drivers will see the food. Will they be ratting out the restaurants to their corporate overlords? I doubt it.