How To Lock Your Bike

What are people's opinions on bike covers as a deterrant. Half of me thinks that a thief might just walk right past it, the other that it might make them curious and peak underneith.

the latter, how many shitty car you've seen with a covers on it? cover implied you're trying to look after it, which also implied that the bike is worth nicking.

bike that look shit and old is a good deterrant, mine have 11 speeds hubs, disc brake, EBB, steel mudguard etc. but never get looked at because of how it look - an old red lugged town bike with fat tyres.