100% reliable, imo.

They're driving:
- a minivan.
- a pre-1990 Cadillac/Lincoln/Oldsmobile.
- any white full-sized American made sedan with gold trim.
- any pimped out Honda.

On the rear window ledge, they have:
- a Kleenex box.
- a Kleenex box in hand-crocheted cover.
- a folded up Afghan blanket
- a stuffed animal collection.
- a ballcap collection.
- any kind of collection.

Dangling from their rear view, you can see:
- a dream catcher.
- a stuffed animal.
- a rosary.
- anything.

Over the back of the driver's seat you can see:
- nothing, because they're too short.
- an old lady.
- an old guy in a hat.

They have more than one bumpersticker or a bumpersticker that says:
- 'We visited (insert name of tourist trap).'
- 'We drove (Alaska Highway, Route 66, etc.).'
- 'We climbed (Pike's Peak).'
- 'My other car is a...'
- 'I'd rather be...'
- 'McCain-Palin '08

Feel free to add.