I woud tend to agree and disagree at the same time. Your state itself "Ultimately, the retailer is responsible for the unpaid rebate according to the FTC" is deceptive in marketing as well. If you read FTC ruled against BOTH Comp USA and QPS technologies. The retailer AND the manufactuer.
Just some backround I do work in the industry, and as a consumer I personally negotiate with mail in rebates
Any legitimate "dealer" will always honor the price advertised (thats with the rebate included). As long as the consumer doesnt procrastinate and supplys the requested docments rebates on the whole are fufilled (They take a long time paitence is also needed).
There are the rare cases where you get rejected for no apparent reason, thats when you should go back to the retailer and thats why rebate centers send out rejection notices so you can overturn them in case they made a mistake. Other wise, yes, if a rebate isnt honored within the "stated" time periods (please get out that magnifying for the fine print) the retailer IS ultimatly responsible. Thats because they had to advertise too.
The worst thing I did? Lost a 100$ rebate with Nikon! Why? Cuz It was recycling day and i threw out the boxes and lost my upc codes =(. Whos fault? Mine and yes like i stated I work in the industry