Quote - ...and where's the ice?...;)

What a free glass of water and no ice... How Dare you!

As for the subject at hand I can tell you part of the reason why some site (including mine in the past) had you register was because of the interface using to run the site. When I was strickly using just a shopping cart as a front end to my site you had to register to download because the site looked at it as a purchase.  Also this helps keeping track with what is being downloaded and how often it is.
With my new site (same site different makeup) you don't need to register to download freebies as of now, how ever I maybe changing this due to high bandwidth usage and I get charged extra a month if I go over my quota as with most small sites. I think this is why Rosity, 3dcommune and other sites have linking for freebies.

Poserverse The New Home for NYGUY's Freebies