I carry my laptop in a padded backpack (not in my saddle bags or bungeed on.) I have a laptop security cable, so I could lock it to the bike, but I don't, I take it with me (it's in a backpack so it's easy to carry.) I use the security lock when I am at Panera Bread, library and other places when I want to go get a drink refill or use the restroom, otherwise someone I trust is left looking after my laptop. It's not the cost of the machine so much as the pain in the neck of setting up a new one and recreating any data since my last backup!