my JYD II is actually fairly easy to centrifugal open out of virtue of its big well balanced blade and smooth action. I still carry it now and then , but I avoid carrying it were I might see or be stopped by cops. it really ought not to get me into trouble though, its not designed to be opened that way after all.
when it comes down to it its really more dependent on the cop than the knife. if its an asshole cop having a bad day you can get in trouble for carrying a case slip-joint it seems, they'll fabricate a reason why you're up to "no good", maybe you won't get a criminal charge but they could still haul you in. good rule of thumb is just be polite and friendly with them, most of them are nice enough and won't give you too much of a hassle about it so long as you show them you are a decent responsible person.