I took a look at the US Air Force subreddit[0] and lots of people who maintain these jets are skeptical as to the accidental nature of this incident. According to several comments there are many physical failsafes that would need to be deactivated in order for this to happen. The incident occurred in Belgium but it’s hard to believe their F-16s are significantly different.
Well, if it's true, we finally have a real live answer to the age-old question in Iron Eagle: "Dad, will the Maverick fire if we're still on the ground?" [1]
The military leadership in belgium also commented that it had to be a very unlucky combination of circumstances, but they didn’t want to say more without further investigation.
Note that the belgiam army wants to buy new war planes sooner or later and that the whole buying procedure has been affected by mismanagment, unclear pressures, etc. (as reported in the local news). So this could be done on intent to discredit the F16, etc.
I wouldn't call the F16 critical. They might even never have been used for an actual mission within Belgium. That nuclear plant though, that is something else. Perhaps also not critical from a 'need this or no more electricity' point of view, but safety-wise this a couple of magnitudes worse than an F16. Word on the street, apparently originating from people working there, is that it has something to do with Engie/France showing off they can do whatever they want.
[0] https://reddit.com/r/AirForce/comments/9nyorn/belgium_techni...