It's not come up for several years but I now live in a ground floor flat... I actually don't think anyone will knock but if they do then I won't be answering.
if you want them to knock, then tell them by having a carved pumpkin or suchlike at the front. they are just kids (5 - 12 or s) and going up to someones house is scarey enough - give a little encouragement by saying 'please knock, i'm up for this and there could be a treat in it for you' (in the form of a haloween sign etc).
people moan about the loss of fun, and children not being children, so why not encourage both.
Have guilt tripped mum into getting goodies in hahahah i LOVE halloween so i know when i have a house ill defos answer and probs like anoku have place done up xxx