When I was going to college one day a flatbed truck came onto the college campus in the daytime, 4 guys got out of the truck and lifted an entire bike rack with 10 to 15 bikes on it and drove off, they never got caught.
No lock is foolproof, and if they can't get the bike as a whole they'll simply strip parts off it. If you're worried about losing your bike to theft the best deterrent is to buy a used bike for around $250 and ride it to work or school, and lock it up with a nice $45 lock. It doesn't make sense to take a $3,000 bike and lock it up with $250 worth of locks only to find them defeated.
Also lock warranties like Kryptonite for an example rarely ever pay out on a claim, that isn't because no one ever steals a bike locked with those locks, it's because of all the loopholes you have to jump through to get the policy to pay out! Loopholes like, when you first buy the lock you have to send in your original receipt and box with the UPC code, no problem right? except when you have a claim they want you to send in the original receipt and box with the UPC code! How's is that possible? But that's not the end to the problems, you have to have a police report and most large cities won't bother doing a police report because they don't have the time nor the manpower to follow up on some "stupid" stolen bike. Then you have an appraisal of your bike that is less than 1 years old, you have to send back the broken lock; you have to take detail pictures of the undisturbed crime scene at the time of day the bike was stolen including what it was locked to, pic of the lock lying on the ground or wherever undisturbed, a view of the area that is large enough for them to determine if public viewing was available (if parked in a dark alley or some such infrequent traveled area the claim is denied), there were some other requirements too I can't recall right now. Also if the lock is 2 or 3 years old (can't recall the age this has to happen) you have to buy the extended coverage for another 2 or 3 years, after that you have to buy an entirely new lock to continue the protection. When Kryptonite was questioned a couple of years or so ago about how much in claims have they paid out over the years their response was that it was closely guarded corporate secret to prevent competitors from finding out! Right.
So skip the hassles of lock warranties, skip the hassles of finding your bike gone, and just buy a decent used bike so in case it gets stolen you won't be crying your eyes out, and save the good bike for weekend rides or when you get home after work. Of course you can always claim a stolen bike on your homeowner's problem with that though is that the deductible is usually $1,000 so that won't be much help plus it could raise your rates.
