Just be ware of the DOT police if they pull u over for that and you can't prove its DOT compliant you're in for quite a hefty citation.
Dot police are state police who patrol the highways and they don't bother with speeder or what small cars do they look for semi's and trucks/SUVs towing trailers or carrying forgen objects via their tow hitch. If I remember correctly citation are based on three different categories: weight, length or intended use and in your case it's intended use is to inflict harm to those who might rear end you... Intentional harm usually lands you in jail so just a heads up man I've seen it happen to someone I know how had a spike in the receiver and his intentions were same as yours "keep your distance or else" he never served jail time but he was arrested, booked and posted bond the same day. The truck however was held as evidence at the impound lot, and the final outcome costed him nearly $10k in impound storage fees, lawyer and a loss of license privileges for 3 months.
Remember any thing you put in your receiver hitch has and must be Department of transportation approved otherwise it's illegal.