It occurs to me that intelligent beings, who have mastered interstellar travel, could make themselves known to the whole population of the World if they wanted to - black ops or no black ops.

I also think it's unlikely that they would regularly crash and allow government 'spooks' to collect the wreckage.

But ... hang on ... they could be in cahoots with the government ... and they could be planning to ally themselves with the REALLY bad government/corporate bad guys or they might even be giant lizards who can disguise themselves as government/corporate bad guys and then they'll ... what's that!! Oh my god it's a giant corporate/government bad guy lizard and it's eating my leg ... aaaarrrrrgh!!!!