Many receipts, including those from Home Depot, have UPC code numbers.
The UPC code shown on the receipt can be Googled, or typed into this data base:
http://www.upcdatabase.com/itemform.asp
You may find that the resulting description and picture reveals a building material item that is consistent with the insured's claim for emergency repairs. You may be able to verify that the item is plastic sheeting, garbage bags, window screen material etc.
You may also discover that the item is a tool, or an item totally unrelated to the claim.
If you want, you can save the photo and/or description that comes up and save it to Xactimate photos, to document the reasonableness (or unreasonableness) of the insured's claim.
for example, suppose the insured submits a receipt that says "081725208964 208R 3.5 Gal
When you google the number, the second result is:
If you click on the link you can even see a photo of the roof cement, and you know that the receipt is a legitimate roof repair item.
If the description and/or photo comes back as a 6 pack of energy drinks, maybe that will be something the policy doesn't cover.