To add to what reaperman said about no existing contract: I can't just send a random stranger an email saying "you agree to give me 50$". There is no existing l

To add to what reaperman said about no existing contract: I can't just send a random stranger an email saying "you agree to give me 50$". There is no existing legal relationship to make that claim. IANAL. However I find that with law, you can just imagine how sociopaths would abuse a system. If you don't see that happening, then that's not how the system works.