the only way to suppress the "Peer-Assisted Networking" popup is to not use peer assisted networking. specifically, if you create a NetGroup or group NetStream, that popup will appear *unless* you set GroupSpecifier.peerToPeerDisabled=true. disabling P2P is only really useful in a pure IP multicast scenario. setting that capability on a group makes it impossible for a client to have any peers, so the client's upload bandwidth won't be used.
the point of the popup is to alert the user that his upload bandwidth *might* be used in a P2P context, which can be a problem for some people/organizations. there is not, nor should there be, a way to suppress that notification.
if the user is a frequent visitor to your site and grows tired of the popup, he or she may check "remember" when hitting "allow" or "deny", and that choice will be remembered thereafter. when the choice has been remembered, the popup will not be presented, and it's as if the user made the remembered choice.
I am figured this, and it seems logical.
Thanks again for your support.