Maybe I'm too optimistic but I think the net risk is reduced with more readily access to updates. The terrorism line just really doesn't strike me as a likely threat. Regular bug fixes and improvements to daily use are likely to save far more lives. Besides, there should be so many audit/checkpoints in front of the release chain, that scenario just seems implausible (but I do conceed that stuff can also fail or be bypassed- let's hope Tesla and other manufacturers have decent IS engineering)