In the case of Toomer’s Corner it probably isn’t vandalism since the school doesn’t object and in fact probably encourages it.
As a general rule tho, I do think papering any place is vandalism. Pretty tame vandalism as it is not permanent.
BTW, I have been to Auburn (and Opelika too) many times. I have even competed at Auburn. Our old coach was an Auburn alum and they let us drive up from Troy and practice on their indoor track.