Hey guys!
Uhhh, this story seems somewhat fishy.
They have not eliminated any parts of the U.S. constitution lately, right? I mean, they might be able to ask you questions whilst pulled over in your car, but, unless, they clearly see an crime/criminal activity, then, without a warrant, any search and/or seizure amounts to an unlawful search and seizure.
Remember you should NEVER consent to a search and NEVER admit to anything prior to a search. If the cops do not have (or can not get) a search warrant, then after some pleantries, tell them to have a nice day and inform them that, unless they have any further LEGAL reasons to hold you, that you are proceding on your way.
If they think that they have a good cause/case, then then can call a judge and try to get the judge to give them a search warrant. If they can not make a reasonable prima facie case to the judge, then a warrant will not be issued. (However, they can, and often do, "judge shop", that is they try several judges until one of them will give them a warrant AND/OR they know some judges who will always cave-in to the cops.) BUT, I don't think they are going to go to that much trouble over a few joints.
A lot of judges would be pissed off if cops were always calling for warrants and very few of the resulting searches resulted in any charges.
I suspect that the reason the cops were "lenient" was because they knew that any half-decent lawyer would get any charges resulting from the seizure thrown out in a heartbeat.
Having said that , though, some cops can be nazi cunts (as in fuck the laws, I'll do what I want) so who knows maybe they would just shoot your ass and dump it in the woods.....no legal problems at all there.