Architectural / urban planning slang: a test to see whether new visitors to a house can easily locate the front door. A quick measure of a home's external user-friendliness.
The city commissioner who led Portland’s effort to regulate snout houses said, "Basically, we want a house to pass the 'trick or treat test, so when kids come around to trick or treat, they actually get a sense that somebody lives in the house, and they can find the door. Imagine that."
A protruding garage, oddly placed front door, or generally weird architecture may cause a failure of this usually hypothetical test. A house that looks as if it would completely thwart candy-mad children at Halloween is probably ugly and uninviting, discourages friendly activity, and therefore doesn’t promote a safe or aesthetically pleasing neighborhood.
NY Times - “In Portland, Houses are Friendly. Or Else.” - http://tinyurl.com/fvrgx
”Life in the New Old Neighborhood” - http://professoryeti.com/20040630/features-urbanism.php