Completely agree, and anyone with any foresight would insist on something more robust. But very often the courts have to deal with situations where the parties did not have that foresight and instead proceeded to do business with one another on the basis of informal or very flimsily documented arrangements. And it falls to the court to look at what little evidence there is and determine (to the extent they can) whether there was an agreement and, if so, what the agreement entailed.

You would actually be surprised just how much business is conducted like this.

I don’t think this is particularly surprising. Handshakes can form legal contracts, and contracts can be formed orally. There’s no reason why an image couldn’t indicate acceptance of a contract, generally speaking (certain specific types of contract may require additional formalities).

But I agree that who upvoted a post shouldn’t be federated.

This also surprised me. I wonder is it necessary for technical reasons to prevent repeated upvoting of a submission by the same user?