These are good questions mustard.
In legal terms, Adam and Eve were not capable of having the mens rea to commit any "crime". They cant understand "crime" itself.
Hence, the simplicity of the command.
It wasn't even about a single, isolated tree beckoning them. It was a garden. There were trees everywhere. All blending in and looking the same or similar perhaps.
In short: By what mechanism did God expect Adam and Eve to do "the right thing"? And for what reason is the ultimate price appropriate or justified?
If I'm understanding your question correctly, that mechanism was trust. Assuming that Adam and Eve were as ignorant as you propose, it would be trust. The scriptures tell us Adam deferred to God, knowing he was inferior to God, not equals. He knew that much...that God, by virtue of being 'superior' would know better.
The scripture also reveals that they understood that death, whatever that was, was not a desired thing. They had enough capacity to put not following God's command as equaling death, as equaling not a desired thing.
How do we know this? Because they had stayed away from that tree, until the snake shows up.
Also, why is Satan a "master deceiver"? Seems like deceiving Adam and Eve would be like putting a bacon treat in front of a puppy..
Here, one can say "but there was bacon everywhere else".
Wether satan is a master deceiver or not... well as you can see, many folks here couldn't point to the actual lie he told. In fact, they kept stating he told the absolute truth. I would say that takes some skill.
As for the ultimate price being justified. People of faith will always defer to God, always. People without faith, obviously never will.