I always carry my SI vertical computer bag as a carry-on and always get looked at odd because of all the over-sized clasps, etc...I refuse to take my tank off going through the metal detector (I'm not allowing airport security to scratch my baby up) so I've never really gotten questioned about it, although I ALWAYS get asked to pull my torpedo vault out of my bag and show them. I'm sure it looks very odd in the x-ray machine, lmao...