AMR parking reservation

Hey folks, quick question I can't seem to find the information online for.

I wish to hike Giant mountain and would prefer to not have to fight for a parking spot. There's an AMR lot right across the road from the roaring brook trail.

If I reserve a parking spot at AMR, is there any issue if I just leave the lot by foot and walk across the road to the trail I want or is reservations only for people using the AMR trails?

Thank you!