lol you still pay the gst so you get 2.50 from every 2.75 back
and seremify, I've tried to find supporting documentation on tag providers/toll sites, but can't. I know for a fact though if you do have a tag but the plates aren't linked, then they'll just send you a bill for the toll +$10. $10 is waived if you pay with your account and not credit card/cheque/whateva.
Would just need to log onto the net and pay via your etag and you only pay for the toll (no admin/plate finding fees). That would work out better if one car makes it through a lot less.