Few quick questions regarding smoke

[PorkNBeenz]

Just a couple of things I haven't been able to find any kind answers to in the Game Guide or through forum searching:

Does a unit in a hex containing smoke gain a bonus to its ability to remain unspotted? Or rather, considering the way spotting works, do units spotting into a smoked hex have any kind of penalty?

Or does smoke simply act as a LOS "wall", stopping anything without TI from seeing through it?

Along this same vein, does a unit in a smoked hex gain any kind of additional defense modifiers outside of those provided by terrain and move status? One would think a thick cloud of smoke covering a 50m area would make hitting a target inside it somewhat more difficult, but seeing as this is a game (albeit a soundly modeled one in most areas) I figure it better to ask than assume reality applies in all cases.


Thanks,
Tom