There are tools to easily bypass all of that shit. How do i know? Lost my car keys and called an auto locksmith. For $200, I got a brand new key that started my previous corolla{with the chipped key}.
It depends on what type of car you have as to how easily it can be bypassed - it also varies from location to location, depending on local regulations.
For example, in Europe, any car first registered after 1 January 1998 must have a factory fit electronic immobilisers with specific security features (such as anti code-grabbing or rolling code type systems) so stuff like "resistor keys" are not legal in Europe.
There is quite a big market for replacing lost keys, etc. and the factory fit systems tend to make replacing keys very expensive - and replacing all keys exceedingly expensive (as most systems require that you already have a coded key present before you can code a new one).
As a result, a number of companies have found security vulnerabilities in the immobiliser systems, and sell exploit units which allow locksmiths and other technicians to reprogram keys and immobilisers in ways that the manufacturer had not intended.
As an anecdotal, my brother had a 2006 Audi A3. He accidentally lost one key down a drain, and then lost the other key on a night out. He called the audi stealership who quoted about $3k to have the car towed, to get a locksmith to break it, and then the ECU and immobiliser module would have to be replaced, before a new key could be supplied. My brother ended up taking the train to work, and called a "security specialist". He gave the security guy his home address and arranged to meet at 6pm with $400. He turns up at 6pm, and the security guy is just chilling. "Oh. I wanted to get off early, so I didn't wait for you to turn up. I've already reprogrammed the car. Here are your 2 new keys" - and that was that. We don't know what the security guy actually did, but we did notice that some of the normal "safety features" and "anti-lockout" features didn't work properly (e.g. if you left a key in the trunk, normally the trunk should normally refuse to shut, unless you first lock the car using a different key) - so I reckon the guy used some sort of vulnerability to flash a cracked firmware onto the immobiliser unit.