With regards to legal rights of a rider when it comes to a legitimate police or military checkpoints, it's based on my recent experiences and through advise of my bro who happened to be in PA/SOG.
normally, when approaching the vicinity, you shall immediately show your intention that you will thoroughly cooperate with them by means of gradually slowing down and by flashing the signal light that you intent stop at the road shoulder. then, as a gesture of good faith, immediately lift up the protective shielld/lens of your helmet and if possible, let them see you face to face by removing the helmet (sometimes, when police and military personnel manning the checkpoint had noticed that you're very cooperative, they will be the one to ask you not to remove your helmet anymore). greet them casually and with respect for it was normally eases any tension. remember that those personnel may have already been there for long period, tired or anything that would express disappoinment. show them that you're prepared for such. your license and registration were the first thing that they will scrutinize, so make sure that you could easily access with it and present to them. normally, they will asked you politely to kindly open the u-box (if there's any, but for our sniper, they used to know that we haven't).
this is the usual procedure that the authorities used to deal with riders. it was just gone wrong when a rider has a problem regarding his license and docs. they will surely noticed if a rider was uneasy. sometimes, there are checkpoints that are strict when it comes to dark lenses of helmets.
they keyword for such situation was "full cooperation", indeed, we have the rights regarding privacy and respect. but sadly, because of lawless elements that uses motorcycle as their escape vehicle, we've been so tight into the eyes of the authorities. thus, there was instances that the situation in a specific checkpoint was slightly tense because some personnel manning the checkpoint were tightly gripping their weapons while approching the rider. it should not be happened should some bikers knew how to affirm their cooperation.
therefore, it will be in our side as legitimate riders, to turn such event into a brighter one. we must deal with them as if we are without worries and fear because we are law abiding riders. should you could make it, you will noticed that they would deal with you lightly and friendly.
hope this will helps a bit. ride safe!