I'm on H1B visa and during past 4 years I have entered US around 10 times. Every time I had laptop with my that had full disk encryption either on Windows (True

I'm on H1B visa and during past 4 years I have entered US around 10 times. Every time I had laptop with my that had full disk encryption either on Windows (TrueCrypt) or on Linux (LUKS). Also I had with me external HDD with full disk encryption on it (TrueCrypt). Nobody ever asked me to look at my laptop or my external hdd. Two times they looked through my larger suitcase, but not my carry-on where I have my laptop.