Not sure of the legality, but I wouldn't. An ASP requires you to get up close and personal. If you have time to open it, you probably had time to come up with a better plan. Just my opinion.
Given that for most here the only other option is a blade and spray, I'd take the spray & baton. You are going to get more distance, but just as important as it is to learn how to defend with a knife the same goes for a baton.