There not especially hard to steal. In fact, on Integras, theives have come up with a novel way of disabling the alarm. They use cutters and make a hole in the splash shield in the wheelwell allowing them access to the inner fender which also happens to be where Acura runs the hood release cable. Once under the hood they go for the battery or siren. The Civics are bad too, they really should have been more security oriented instead of service oriented as far as thier ignition switch design. THese factors combined with the fact some people sink some SERIOUS money into these cars and there popularity (the expensive parts are in demand and move quickly) means if you own one with any level of modification, you just about NEED increased security.
Thankfully, more cars are coming with transponder based key anti-theft systems anymore which has cut down on many thefts.. Ford's PATS is a decent setup that comes to mind. However for some reason, GM's is somewhat disappointing when it comes to this. The keys are just plain old tumbler based credentals, as many of you have found (specifically pertaining to Escalades) when you go to get your keys copied. GM uses PASS-lock, which uses the rotation of the lock cylinder to authenticate the user. Its a start, in that just crossing wires doesn't net the thief a running truck, but say, picking the lock DOES. I think the later generation PASS-key setups were a more secure choice.
Regardless, automotive security is a big thing. More people are recognizing this, and buying aftermarket alarm systems. I just wish there was better quality from the installers who customers depend on to keep thier vehicles safe. (Fun game: if you have had a "Pro" install your alarm in any of your vehicles, next time your cleaning your car see if you can spot the plastic cube with wires coming out of it pictured under the siren in the area under your steering column. If you can, you have just found out where to bypass your alarms starter kill. Look for wires that just "don't match" the rest of the vehciles wires, that usually leads you right to it. If you can't find it, congratulations maybe you had an installer who took pride in doing a good job and ensuring your vehicle remained YOURS.)