I figure it's a safety standards and liability issue. If companies like CEC put every precaution into the sensor, then they can't be liable if some idiot compromises it. But if it can be compromised as easily as an off switch in the cockpit, and then a bunch ship captains kill themselves by playing with it, that's lawsuits and a degree of bad press, even if it's not strictly the fault of the company. If the company can reasonably say they put their best safety features into it, and the owner compromised it on their own by digging into the hyperdrive and/or navicomputer, well, condolences but it's we're not liable.
Of course, it's kind of hard to know for certain when a ship is pulverized by a planet, but whatever.
Of all the things I have read about SW lately (in a setting that has Space Wizards and Superweapons), this stands out as the most realistic and sensible thing I have come across; safety standards and legal liabilities. Makes me want to go out and buy a book on the CEC/Corporate Sector just so I can learn more.