If serious document destruction has actually been taking place in Alberta, chances are good it happened well before Albertans marked their ballots, let alone before their votes were counted.
For one thing, if the outgoing Progressive Conservative government led by Jim Prentice had access to quality public opinion polling -- as it most certainly did -- it would have been pretty obvious to it a few days before May 5 what was going to transpire on that day, and that the likely beneficiary would be Rachel Notley's New Democratic Party.
For another, nowadays documents are not destroyed with paper shredders as effectively as with their digital equivalents -- giant horseshoe magnets or something.