Don't know about the Hebridean methods, but a bit further south in the Solway estuary, where they have one of those tides that will outpace a galloping horse, it was supposedly the chosen method of execution to tie the victim to a stake embedded in the mud and let nature do its thing. Doubtless the resident gulls would enjoy the remains.

I suppose a refinement might have been to leave the victim where the tide might, or might not, just quite drown them.

Geese are herbivores, yes, but all the nice gulls love a sailor.

OK, getting my coat now.