They asked whether the man was authorised to approach prospective clients out of the blue.
"Your employer, when questioned, was at a complete loss," the judge said.
When Gray was seen by the residents of the house in the middle of a Tuesday afternoon, he told them he had been sent there to complete an inspection of their window furnishings.
He continued his perusal of the house, entering all three bedrooms, the court heard.
While doing so, one of the occupants called their landlord and asked whether such an assessment had been organised.
They gave him the boot when it was clear he was lying.
"I have to say the whole thing is troubling," Judge Phillips said.
The judge was so concerned, he ordered a psychologist's report to hopefully reveal some answers as to what had driven Gray's strange behaviour.
But the defendant was "less than forthcoming" with the health assessor.
He would not speak in detail about what had happened or about the 26 previous dishonesty convictions on his rap sheet.
Duty lawyer Max Winders said there had been a 20-year gap between Gray's offending in the '80s and a new batch starting in 2006.
Which was a mystery, because the man would not discuss his personal circumstances.
"I have no doubt really, in your mind you were entering the house with some kind of dishonesty in mind. I can't put my finger exactly on what it is," Judge Phillips said.
"I'm concerned you work at this carpeting business and you seem to use that job as a pretence to get into people's properties."
Gray was convicted of unlawfully being in a property and sentenced to three months' community detention and 80 hours' community work.
"I warn you, Mr Gray, any further convictions of this kind and a term of imprisonment is inevitable."
