I have seen a lot of kits for sale to prevent the theft of saddlebags and to keep them from going airborn on the highway. I personally am not worried about theft because once the pry the lid off I prefer to have my insurance cover new bags. I am concerned about fly offs though and have recently come close to losing one. So being thrifty (better word than cheap SOB) I put my own together.
Went to Lowe's bought 4 Hilman U nuts 5/16-18 and bought 4 each 5/16-18 SHCS lock washers and fender washers. Bought grade 8 fasteners and all items are galvanized. Very seldom do I ride in the rain with lid off bag so I opted to go without the stainless screws. Yes, someone can unbolt them with a 1/2 inch wrench but not when I am going down the road. For added safety I put a dab of blue loctite on the threads of the screws. Total cost less tax $5.72 Security for fly offs Priceless.
So if your like me and are only interested in the bag coming off go for it, cant beat the price.