In having been involved with this with a retail vendor previously, what a lot of people don't understand is that MAP goes beyond the posted sale price on the site. In this case, for example, yes, the vendor was selling the item for $649, which is obviously compliant with the MAP agreement. eBay was willing to eat the extra $100 to drive traffic to the site, essentially refunding the vendor; hence, it would appear that the transaction wouldn't violate MAP agreements.
However, MOST anufacturers have covered this loophole in their MAP agreements, and per a Uniden representative's commentary, it would appear they are no exception. The issue is over what constitutes "advertised price." The loophole essentially closes a gap here, whereby, for example, someone goes to eBay and clicks "buy it now," and scanner goes to your shopping cart. Once you get there, you apply the coupon, reducing the price to $549. However, what a lot of people do not realize is that the MAP agreements still consider this price, in the shopping cart, as an advertised price since the transaction has not been completed. Hence, that $549 discounted price, pre-transaction, now violates the vendor's MAP agreement, even though it's in your shopping cart and you are ready to order the item. The manufacturers have already closed those loopholes, i.e., the final dollar value of the MAP-protected product CANNOT be reduced by any sort of a site-wide discount prior to the final transaction, otherwise it violates the MAP agreement. That "advertised price" carries through right to the final point of sale. I didn't make the rules. I realize that many are acerbic over not being able to save $100, but those loopholes are already closed by the agreement.