The other day I heard of a flute stolen from inside a car, and it makes me so upset that I just want to give some simple advice: NEVER LEAVE YOUR FLUTE IN THE CAR!
Yes, sometimes it's a drag to carry one's flute around (be grateful you don't play tuba…) but consider the risk involved: most insurance companies either charge more (a lot more) for this coverage or will not reimburse for an instrument stolen from a car. I believe the reason is that it must be pretty easy for thieves to break into cars. Sad but true.
So every time you're tempted, just think of how you'd feel discovering that your flute has DISAPPEARED, along with the investment it represents. And then, just tuck it under your arm, or put it in a fun bag, and hang on tight! (PS, let's hope this stolen flute is recovered!)