Heavy dude... as growers we tend to immediately assume that we're busted when someone looks in the general direction of our grow, or anything weed related for that matter... comes with the shitty law I guess
I reckon you should just keep that one seedling going. One seedling is easy to dispose of quickly. If by some off chance the cops do rock up at your door, check who's knocking before you open, if its them quickly pull that seedling and stuff it somewhere in a pillow case or something... or flush it if you can, wrap it in TP first.
Don't let your paranoia for the law let you execute one of mother natures greatest creations