On the other hand, being able to scan a planet ahead of time to see if there is a trade resource there could be incredibly powerful as it will also (presumably) tell you what bonus tiles a planet has. This might not matter on low quality planets. But on higher class planets it could be very valuable info indeed. As well as seeing tile placement ahead of time for the adjacency game.
I realize that people have clamored for the ability to see what a planet looks like before colonizing for, well, probably forever. Hell, I'd love it myself for obvious reasons. 
But I reckon there must be a reason that it isn't implemented (even if it is only a coding concern).
The way I look at it, trade resources really are Super Bonus Tiles, that already have their bonus building on it. But it still is a bonus.
Mind, I colonize all planets eventually (putting a lower priority on low class planets, but still colonizing them), so for me it's not that big of a deal. But I think we might want to see the side-effects of knowing what planets have what trade resources on it from an implementation/balance POV.
