I just had to chime in on the history of rebates. They first started as a way for manufacturing companies to clearance out merchandise. Whether it was for a new model or just dropping the item or getting rid of extra stock. The rebate was supposed to guarantee the savings to the customer (driving sales!) whereas dropping the wholesale cost and/or MSRP may not translate to the lower price the manufacturer had expected. I learned this from my marketing research classes in college. I had one class just on coupons and rebates (imagine how boring that could be!!!!)
Today, those types of rebates still exist, but marketing people have realized they serve other purposes. Rebates not only come from the manufacturer but from stores themselves to act as a promotional tool as well. Store marketing people learned that they could effectively drive a full price sale by offerring a rebate that was appealing enough. They also learned that some people will forget or file the informaiton incorrectly. Rebates, like coupons, are items that some people just don't bother with as well. Some estimates show that rebate fulfillment can be as low as 20% for lower-dollar rebates (and as high as 80%). Running a rebate would almost always end up with more dollars in sales versus putting the item on sale for that price. The worst 'tweaking' of the rebate world as of late has been to make the rebate not worth the effort but advertise the after-rebate price to drive sales.
Even with these new ways to use/abuse the rebate, none of them involve refusing to fulfill the rebate. That may be more dishonest than anything with these new ways to trick the consumer. I don't like those methods, but they are not illegal.
I do believe there are some comapnies who are purposefully trying to not fulfill rebates, and that is illegal. If they can get away with it, then they'll continue to cheat the consumer. I agree with the OP about going after those companies. With rebates, filling out correctly and sending in the proper requirements for a rebate DOES result in a legal contract for a refund. Companies that get the right information from you are required to give you your rebate - everyone who has correctly sent in their rebates has a right to get their money back.
I believe the only other fishy way of dealing with the rebates are the 'lost' rebates. I would still look for ways to file a complaint about a lost rebate - if enough are 'lost' then an investigation could ensue. Definitely make copies of all documents sent in (and filled out completely, not the blank forms!) I would absolutely send in a rebate with Delivery Confirmation if the dollar value is high enough (especially if the rebate address is New Rochelle, NY!!!!). They can't claim it was lost in the mail if you have proof they received it! Of course, that doesn't work well to pay for DC if the rebate is 2$.
Sorry for the long soapbox, but my belief in marketing is appealing to the consumer to buy your goods. Rebates are very much a great marketing tool, but I hate to see when it is abused to screw the consumer over.