Signatures are a joke, nobody checks them (I used to work in retail). And even if people did check them, they're trivial to forge (there's a copy of the signature on the card telling you what it's supposed to look like!)
I travell alot and I've had my gear stolen a few times, and atleast once a year (usually a month after I get back) I have to go through claims processes to remove charges which start appearing. Total pain, and why I'm suspicious of another system that looks atleast as bad as whats already out there.