Good info. I have been pulled over twice while transporting to the range, once on the way out to Jamul riding with a buddy of mine, and once on the way to Dulzura with my 9yo son. Both times were pleasant and we had no issues (other than the reason we were pulled over). The first time my buddies truck wasn't registered (I didn't check before I got in), he explained the issue (smog failure, 30 day fix it, new to CA due to active duty orders...he's an idiot), LE (CHP) told us to stay off the freeway or they would impound the truck. Agreed it was a beautiful day for shooting and told us a back-road way to get where we were going. Never once asked to see the firearms or even asked if they were loaded.
Second time I was pulled over due to a bad light on my jeep. LE ended up asking my son about firearms safety, complained about the never ending cash flow associated with owning a Jeep and told us to have a good day.
I am pretty savvy about my rights, and do NOT trust LE or Government to preserve/protect said rights. Even with the pleasant experiences I have had with LE and my weapons I have in both instances had my recorder on to protect and preserve my rights. I use a cool little app on my cell phone called cop recorder. It is easily started, will record as long as you have memory, runs in the background so it isn't detectable, and uploads to wherever you want it to.
Also, whenever you "sign" a ticket or official paperwork make sure you put "without prejudice UCC 1-308" near your signature.