This is so true too. I had all my stereo stuff in my cutlass on stock rims for months and never had a problem once. Then I put some 20" aftermarket Panther Juice rims and wasnt a month later my shit was gone, not just the 5gs in sound, but my whole god dam car! Had 2 alarms on it too. Had a bypass alarm just in case and still didnt matter. Like the one guy said if they want it bad enough, they will find some way of getting it.
Sorry to hear about, it happens, just keep your head held high and try not to do up your ride so much and it should be more safe. Good luck and happy bumpings with the new stuff.