True. Write-protected flash drives do exist - I have a 512MB one I use for booting up cleaning tools, for example. Put a tamper-resistant sticker over the switch for software vendors. I know some AV solutions for Windows have come via USB sticks - netbooks and similar sized machines are enough of a market without an optical drive to make that a useful feature to have. I know I'd pay an extra $5 for software to come on a reusable disk, as opposed to a single-purpose DVD. I only burn ISOs for old OSes (XP and the like) - or for machines that won't accept USB boot.