... And make sure you are on the right land...
Two Februaries ago, a survey team came through my land to do a core sample.  They were a block away from the land they were supposed to be at...  Tore down two Plum trees, a grape vine, part of a fence...
There were words, all very calm on my part, and reperations were made.  It did create an interesting situation where A neighborhood group became very active because of the reason the survey crew was there.
Rena