Don't speed maybe? Don't have smashed up lights etc. on your car maybe? If you have to speed then you might want to get a radar detector. If your vehicle has safety issues then fix them on general principal especially if you plan to go a few klicks over the posted number.
Have the guns cased and secured like they were real firearms (as they are termed as unregulated firearms).
Don't be sitting in the driver's seat with a plate carrier stacked with mags etc on and your buddies all dressed the same. I go games with my gear packed and I may wear my pants/boots on but I"ll have plain t-shirt or jacket on vs. looking like you're rolling a convoy in bandit country.
If you are stopped don't run off at the mouth, either disrespectfully or in the vein of TMI.
In other words do not be the low hanging fruit or the first rabbit over the hill. There are lots of other people out there that draw attention to themselves. Let those folks draw the attention. If you do get stopped let the Cop know you're not worth writing up. One car a couple Km over but otherwise unremarkable rolls right by vs. busting a possible terror cell/hold up ring & displaying a "weapons cache" on the six o'clock news that will fill the local quota for a month.
Airsoft, where nothing is hurt but feelings.