Here what I know and have experienced on the subject:
Carrot mentioned something about 7 inch + tools being prohibited, but the fact is that any tools are prohibited on airplanes; I know someone who had to leave 3 inch long Allen keys behind. Luckily, flashlights are not considered a tool. I believe I had read something about 6 inch + metal objects being prohibited, but I also read about some CPFers saying they got on a plane with bigger lights.
To answer the original concern about crenealed bezels; there is crenealed and then there is Crenealed... a few raised dull crown points might not be a problem, but the pronounced sharp edges might definitely get a second look. If you absolutely want to bring a flashlight that you think is borderline, get there early and ask. I don't believe they would arrest you for asking if you can carry an object or not (unless it IS a bomb), especially if you intend on leaving it in the car or check your bag if it was refused. I once forgot a screwdriver in my bag and the guys at security let me go back and check my bag in.
I inquired a year ago about crenealed bezels because I was considering buying an E2DL (talk about a real sharp bezel) to go camping and I was told that if I crossed the border by car it was absolutely not a problem.
My take on this is that if you like your light and don't want to risk having to leave it, put it in checked baggage (and risk it disappearing) or carry smaller lights. I just came back from LA, which is an international flight for me, with 3 lights (Quark123, Zebra SC51c and LD15) that I either put in the tray of left in my carry-on and no one ever bothered. Actually, my wallet was much more of a concern at LAX since they now systematically scan everyone (D'OH!)