you do realise that allowing only seedbox would require a
HUGE database of ips all over the planet that have seedbox offerings or/and vps/dedi server
Example: Me as a user go on a small island as Ibiza and purchase 5 dedicated servers, turn them into seedboxes, installing rtorrent and other stuff.
How would your tracker know that i'm using a seedbox without contacting you ?
This would be a waste of time for most of the users.