Those of you who worry about uniformed buyers are no doubt very kind and caring people. However, rules/laws can never prevent some individuals from acting out of stupidity or ignorance. As well intentioned as such rules/laws may be, they are usually ineffective and always carry a cost.
It is not Disney's responsibility or even in its own best interest to get involved in resales. First of all, as others have posted, the buyer is already subject to all the rules that applied to the original purchaser. Secondly, if Disney did institute a requirement for a signed product understanding list for resales, where do they stop? Have they then opened up a "liability can of worms" if they don't do everything/provide all the documention that they did for the original purchaser? I can imagine someone claiming that since Disney did "x", he/she had a right to expect that they would also have done "y" and were "harmed" because Disney didn't. There is cost involved here and I don't blame Disney one bit for not wanting to increase its expenses without a corresponding increase in value. I also do not think it is right for a knowledgable purchaser to pay extra just because some are not smart enough to do all their homework.
IMHO, it is the buyer's responsibility to understand what he/she is buying with a resale. Buyers who are uncomfortable with that should either purchase directly from Disney or hire a competent lawyer to review the contract on their behalf. In fact, it's a good idea to have an attorney review the contracts purchased directly from Disney. A few hundred dollars to protect thousands is well worth it to me.
JMHO. YMMV.