Title says it all.
Yes and no. You would have to pick up the item first, then lose it or use it up, before that would work.
Yes. For an example, look at Dungeon Stompage.
And another example: Kill Aman's Mustache. A lot of BerkaZerka's games are like this. Very convenient. I wish the Homo Perfectus series did that, too. It's so annoying, taking all of those items at the start.
$ITEMSTATE01 := 1
Means the player is give item 1. Much easier to give items with scripting than just leaving them on pages.