As already pointed out in another comment, don't volunteer that you have pot on you. At least make 'em work for it. Oh, you were thinking they were going to go easier on you? It doesn't work that way. On the one hand, yes, current marijuana laws in most states and at the federal level are ridiculous and unproductive. On the other hand, as a Washington resident what do you think I left at home on a recent motorcycle t…
Actually it does.
I've had several incidents in states where medical marijuana is legal, but you have to have a card. Possession without the card is illegal. Both times we were up front with the cop and he thanked us for being honest. He only gave us a citation for a fine, confiscated our weed and then sent us on our way.
Or you can "make em' work for it" like you said. You can bet the cops are not only going to get you on the possession, but then you get arrested and now if you're driving and you test positive for THC, now you're looking at an impaired driving or driving under the influence, which can get you reckless driving or reckless endangerment if you had passengers. If you were a real douche to them, then they start looking at obstruction or impeding an investigation. Sure, if you get yourself a decent lawyer, most of those charges could be dropped, but that doesn't change the fact you spent a few nights in jail, had to post bond and now have a court date and now have to explain to your employer why you missed three days of work.
Trust me, it's always better to cooperate with the cops. Being a dick is just going to get you more trouble.