I've never had any problems with packages disappearing from porches, though I've heard of occasional rashes of disappearances from others' porches. I'd probably want to sign for packages of obviously valuable things, or bring them inside very promptly

People pretty often leave stuff out on the front sidewalk AS free stuff, with the intention that others take it away. But that's the sidewalk, not the porch.

Your pumpkin will be fine. Carve away! :) Welcome to the neighborhood.