John has said it all.
If the retailer is large enough to be a full Partner at manufacturer and retail level, then he certainly has the facility, but is risking his partnership with Microsoft.
I would imagine, at this stage, that the catch migh be the watermark.
I am not a manufacturer, but am a full parner and Technet subscriber. Yes, I have legal downloads and activated installations. But they do come with some regulations regarding their use. This restricts the user very much to his own premises. Whilst the system can, and often is, abused, the perpetrators are easily traced through the dedicated activation mechanism, and the penalty, whilst not landing anyone in jail, is very expensive with a permanent loss of all Microsoft priviliges..