I simply don't tell the airport management anything, At PAE my customers get me thru the gate, I work in their hangars and say nothing. At BVS I am treated like I'm a service provider, the airport management allow me to have a gate card. I don't tell them when I come or go. AWO I have the gate combo, and tell the management nothing. Harvey Field My customers get me thru the gate, and we tell the airport nothing.
Lots of times it is easier to beg forgiveness than to gain permission.
Anacourtes and Bayview (BVS) are the best run airports I frequent, they both belong to the Port commission which have Pilots and aircraft owners on the board, They want us to be free to come and go and fix their tenants aircraft.