As of SFEE 4.1 Hotfix 4, it is possible to configure SFEE so that all new accounts are 'unrestricted' by default instead of the moresecure 'restricted' default.
To enable this, simply add the following line to /usr/local/sourceforge/sourceforge_home/etc/sourceforge_configuration.properties:
sf.user_account_restricted=true
Once this line has been entered, simply restart SFEE to have it take effect.
NOTE: This does not change any existing accounts. If someone was 'restricted' before this flag was turned on, they will remain 'restricted' until the 'site admin' edits their account.