"The Amazing gRace" stamp, Pismo Beach CA

A friend and I recently visited the Monarch Butterfly Grove at Pismo Beach in California (pretty neat place http://www.monarchbutterfly.org/ ) We walked from the grove to the beach, and along the trail was a small sign that said something about the campgrounds. There was a stamp tied to this signpost, a little custom self-inking stamp made at office depot. The stamp printed out the words “The Amazing gRace”. Yes there was a small g before Race. The sign was of course covered in these stamps. Does anyone have the slightest idea what this is and why it was there? A religious connection seems out due to the capitalization. Googling has come up with a merchant marine ship by that name that once docked near Pismo Beach, but that doesn’t make much sense.