It's certainly not the actual legal definition of a search, but I would like it to be defined very broadly, something like "the use of government resources (i.e. taxpayer money) to observe or inquire about any private citizen on private property."

Even though it's perfectly legal for a neighbor to notice something potentially suspicious about me (e.g. that I travel a lot or have a lot of guests), I don't think that taxpayer money should be used for concerted observational efforts without some form of court order.