Sure it is. Try extending this argument to every other kind of business. Most shops, for example, don’t let you take whatever you want off the shelves and promise to mail them a check later. Even if many people would be honest, enough wouldn’t that it would make their business unsustainable (or at least substantially less profitable). Therefore, they almost universally prohibit this.
That’s just one example among many. The logical conclusion of your argument is that it’s unacceptable for any business not to extend unlimited trust to all their customers unconditionally.
