My solution to this problem is to ALWAYS lock every layer that you are not currently working in. If you do switch to another layer to, for example, temporarily hide it and then attempt to add a scenery asset while that layer is selected then you will get a nasty warning message. Yes, it does mean spending time constantly locking and unlocking layers but cases of misplaced assets are greatly reduced as is the time wasted in moving assets back into their correct layers.
I also have a similar "wrong layer" failure rate in apps that do prominently display the name of the current or active layer, so that is not going to be a perfect solution.
Another handy trick is to periodically hide any layers you have been working with to see if all the assets that you believe you added to them disappear from the screen. Any that don't have escaped your "due diligence".