I don't think you understand why this is unacceptable, as evidenced by what you propose "they" will "do next". > The next thing we will see in such contracts i

I don't think you understand why this is unacceptable, as evidenced by what you propose "they" will "do next". > The next thing we will see in such contracts is something like 'under no circumstances are participant's costs associated with event refundable, including but not limited to registration fees, travel costs, bla bla bla.' This misses the point entirely. Presenting a contract after the purchase is not acceptable, period. You do not have to agree to anything after the point of sale, and the vendor cannot make the use of your purchase conditional on any such agreement. If they expect any contract to be valid in court it must be presented before sale, full stop. For more information please see First Sale Doctrine.