AdWords, Product Listing Ads and Ebay
We have many competitors, Sweetwater Sound and B&H Photo are two for example, that run Product Listing Ad campaigns via Google Shopping in addition to offering exactly the same items (same manufacturer part numbers, same UPC, same prices) in the eBay stores. Consequently, they do have more than one listing in Google Shopping for the same products. Are they getting around the "one listing per product policy" because technically they don't control the listing coming from eBay? Do some advertisers (in your opinion) choose to accept the self-competition (and higher cost of advertising that results) in favor of gaining more market share by having more than one listing (i.e. one regular Google Merchant Center submission and one from their eBay store)?