I think the main problem is grubhub don't make it clear that this isn't "officially supported". Imagine someone set up a website claiming to sell your services,

I think the main problem is grubhub don't make it clear that this isn't "officially supported". Imagine someone set up a website claiming to sell your services, without making it obvious they have nothing to do with you, then after accepting jobs would ask you to do them (ok, this comparision doesn't quite work, but I think it gets the basic idea).