[g-b-r]

If there is some degree of proof that he was involved in the transaction (e.g. credit card payments), if agreeing to the terms was a precondition it's unlikely enough that a wandering cat or a curious child clicked the "accept" button for there to be no reasonable doubt (unless he proves otherwise).

By the way, the hypothetic wandering cat or curious child that were to do so would risk of being liable of perjury :|