TexasCHLforum.com

In situations where you have legal right, but risk your at-will employment status, if your gun is in a safe in the parking lot (inside your car), and you happen to have a key-entry safe (not fingerprint or digital), if your vehicle does come up for a search, you can always tell them that you have carried a firearm in the safe before, but not today...and you don't happen to have the key with you today. (suggest not having it on the same ring as your car keys, in case they call your bluff).

It's not a technique I ever tried, but it was bantered around frequently prior to the passage of the parking lot bill.