I hear ya. the keycard is i think NFC or RFID and only works right by the door panel - so it's not like leaving a regular keyless entry key fob in the glove box. the glove box is locked anyway (i think) or i think i can set to only open with a VIN. so, if they're "already" in my car, they either broke a window or had a key or prior card or my phone.
Anyway, having it in my glove box (locked) and maybe even hidden behind stuff (on the fence about that) means i always have a spare card with me, though i should in my wallet anyway. that has me further thinking, for complete "safety" perhaps a photocopy of my driver's license and insurance card in the glove box as well, in case i lose my wallet, phone, and mind.
the ONLY way i see this possibly happening, might be at the beach or a water park etc. where everything might be say, in my wife's beach bag.
i have also seriously considered the ring that doubles as a key (has the key card electronics built into the ring) but i think that is too much even for me.
i think a key card holder that i print in tpu, and wear around my neck at the beach, or even give to the valet, will get the job done.
I do know i don't want to hand a valet just a blank key card, i'll want "something" around it so they can also indicate it belongs to me.
the way telsa is going, i can see 20 of these key cards at the airport park and rides in the future