Um, Deacon, the difference to anyone who has actually used analog tape is obvious. I'm no engineer, just a casual hobbyist who briefly "did sound" for friends' bands. From actual experience, I can assure you that transporting tape on a car-seat is safe, putting it close to big magnetic things (like the steel rollers that support the belt) can ruin it.

OP stated his tapes were old, the recordings on them irreplaceable. They should have been given the same respect as any other artwork that requires hand-carrying.

And yes, I have seen a too-young-to-remember TSO try to check undeveloped film by opening the canister.