The paper tube thing is worrying!!!!
But you would be on a mission if you are out burglaring with a angle grinder!!!!...lol
Yep, just make sure it's insured and data backed up. Any sensitive data should be encrypted if possible. Google Truecrypt.
Kensington locks can be cut through in seconds. My big bike lock was cut through in seconds. If they want it, they'll probably take it. Putting a lock on just increases the chance of damage to it if they don't take it, or if it's recovered, so insurance is probably best.
For desktops, you could also look at an icydock bay where you can remove the hard disk on leaving the machine.
I hate guys like that :/ He's just let any prospective computer thief know how to easily and cheaply get past a lock, negate the customers insurance claim and failed to make it any more secure. He could simply send this information to Kensington ALONE and they would eventually make a better product that doesn't have these problems and at least keep the way to steal the product less well known for the customers that currently have that security. Some people are only interested in getting a little internet fame though I guess *facepalm*.Kensington locks not so good, there really isn't a decent way to secure a laptop or desktop.
http://www.youtube.com/watch?v=as-CPdf-rKI
or
http://www.screwfix.com/prods/42885/Power-Tools/Grinders/Erbauer-ERB017GRD-4-Angle-Grinder