OnRequest Images - A Threat To The Stock Photo Industry?

Today the ASMP (American Society of  Media Photographers) published an open letter written to the Art Director Club (Link). Ocularly the reason is simply that the Art Directors Club is willing to accept "sponsorship funds from On Request Images for your upcoming gala event."

Actually ASMP (and the Stock Artists Alliance, Advertising Photographers of America and Editorial Photographers) is bringing up concerns about the business model’s long-term viability of OnRequest Images:

We have heard troubling stories from photographers who unwittingly engaged in this model [...]
The business model known as 'Custom Stock' does not appear to provide a viable and sustainable income for professional photographers and hence this is not a practice we can support. [...]
We urge you to not ignore the threat that "Custom Stock" brings to our industry.

A bit different Bahar Gidwani (Link): "I've heard nothing but good things about the opportunities OnRequest is creating for artists and the images they are making for their customers." A more detailed response from him in "Industry Comment #10--Is Custom Stock Good for Artists?" and finally a link to the ASMP position paper.