Well, I wouldn't call this "hard evidence", but in the past, I never obtained any compensation from AF for a delayed luggage on an award flight, while I always obtained some with a paid ticket. By compensation, I mean what comes in addition to the reimbursement of expenses you had in link with your delayed bag (e.g. miles, money). If you look also at FB Amex insurances, paid and award flights are treated the same way.