don't know the size and style of haunt you are talking about, but yea, we try to keep certain restrictions in play.
If it looks like it could be leaned on (fence, fake walls, etc) - people will. Test all your walkways for 'reach limits'. Can anyone reach a prop, lamp, heat source, outlet, wire, etc. If so, add more fencing or barriers. If you have 'startle' props, are all the walls/fences around that area (and to its rear) sturdy. A truly frightened TOT of any age/size, has lots of strength when trying to run or jump away from a startle. Adrenalin is a fun chemical, aint it?
Of course idiots have a cunning way of challenging any proofing set before them.
Have clear signs for exit/keep out areas. Hangin props are especially tempting for 10-14 yo boys. They love to 'jump up' and try and touch stuff. If putting something over a walkway, put it high and sturdy.
One issue I have (with a neighborhood front yard setup), is 'friend access'. What I mean is I may have a friend stop by, or the kids of friends - and I may show them a 'backstage' view or walk them around something. If other guests see this, esp kids, they all think they should be allowed back there. Keep any restrictions applied to all, and give any special tours after the big crowds are gone. I also purposely invite some of the neighbor kids to help build or layout the display. These often take their access abit for granted and breach certain safety barriers.
Our worst incident was long long ago at our first house. We had a blacklight on the ground uplighting something in a flower bushes. A 2yo toddler got over there, reached thru the small area and touched the bare bulb. You all know how hot UV gets...Nothing became of it, but we have stayed on edge for the lawsuit lurking TOT ever since.