Rockinbbar: Absolutely - my Rifles are checked every year before season.
And sadly I check "the zero" anywhere from 4 to 7 Rifles for my (lazy) friends - mostly the ones with 300 Weatherby's and various 300 Magnums!
I do NOT enjoy the latter but I respect the game (Antelope, Deer & Elk) to much to let my friends go afield with guns not sighted for two years or longer.
Of course I am retired and have been for a long time and word gets around amongst my still working friends.
Use caution when agreeing to "double-checking/sighting-in" your friends guns - word WILL get around.
Hold into the wind
VarmintGuy