Today had father and two young boys in to see the layout. Figured they were old enough to know rules. One proceeded to push an auto onto the track shorting out the layout. The other manually threw a switch just to see if loco would "crash" into other on siding, fortunately the siding was un-powered and loco stopped short much to his disappointment. 
A few weeks ago a grandfather bought grandson to see trains. Kid was more interested in pushing autos around and gouged a rut into foam street.
Kids have attention span of gnats I am convinced, spoiled no doubt by the violent video games parents let kids play (have to have continuous action stimulus).
So my new policy I will tell visitors young and old (unless they are adult train operator known to me) will be: To keep hands in pockets and just look, no touching ANYTHING. Or::
ACHTUNG! ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!
DAS TRAINMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN.
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Whats your layout policy?
