I always request
2 keys, I keep them in separate pockets--both away from cellphones and other "magnetic" devices.
The + of check/in via cellphone is no waiting on lines, but since I have only ONE CP as I noted in my OP the minus of CP c/i.
I was an "invited" guest, so had special c/i.

I work with beam accelerators all of which have gigantic magnets, the type that rip tools out of your hands.
I have my keycard in my pocket all the time.... never lost one yet.