On a recent inspection in an attic, I came across a truss chord that had been sistered with another piece of lumber as a repair. This can be a legitimate repair, however, there was no evidence of an engineer’s label showing that the repair is legitimate.
A truss is an engineered type of roof system designed to handle loads (i.e. roofing, snow (not much of that in Tucson), AC units, etc.), which then distributes those loads to the load bearing walls of the home. Any modifications to a truss (notches, holes, etc.) can reduce the truss’ ability to carry the load it was engineered for.
Therefore, for the integrity of the home and the safety of its inhabitants, a truss should never be modified except with the approval of a qualified engineer and the work of a licensed contractor. That approval should include a label with the engineer’s signature that is then attached to the modified truss to indicate to others in the future (like a home inspector), that the modification has been properly done.