I have done reviews for NCHaunts www.nchaunts.com. Never been an issue for any of the haunt owners when I do reviews, as long as you provide ample evidence that it's legit. The featured haunts in the area are usually sent out a letter prior to the season asking if they wish to have a reviewer come by. If not, they don't go though in an 'official' capacity. I would be wary of someone who shows up unannounced demanding to go through for free in exchange for 'reviews'.
However, If a pair of free passes will make or break your haunt, you have larger problems than a good review can fix.