The times I got new pedals, I sat on the couch with the shoes and loosened the clips before I put them on the bike. I wasn't taking any chances.
I once made a panic unclip. I can assure you that the clips will let loose if you pull hard enough in any direction.
This is a fence put in with "t posts". Posts are about $5-6 each. You can drive them yourself or pay some neighbor kid to do it. Farmers use them a lot. I've driven way too many myself.