My DH just left LE recently. In all our years going to WDW, I have never seen a discount for LE. Active military, yes. I would love to know if there are deals out there for LE officers.
Years ago when I was in law enforcement there was a $25 cap on the value of anything you could accept. No they can't accept any discounts or freebies, you can get fired.
Not sure what type of LE you are, but I'm federal and we have a recreation association. Through that association, you can get access to ticletsatwork.com. That site has discounted tickets - generally it's a "buy three days, get a fourth day free" type of deal.