Question about Traps

[Retech]

So this guy I was fighting had a whole lot of loaded bear traps in his handy haversack. He said that he could drop them as free actions, so every time he ran away (he was a wizard and I was a cleric), he dropped a few so that I couldn't follow him.

How long does it actually take to set up a trap and can they be all prepped to go inside a handy haversack?

[Doughnut Master]

I don't see how that would be an effective strategy. If he's laying them out one at a time, you could just step around them. If he's just flinging them down, they'd be pretty easy to spot and avoid.

Moreover, removing a set bear trap from a bag would likely cause it to spring.

Why didn't he just use caltrops?

[Cog]

Drawing any one item from a Haversack is a move action. He can draw and drop two... if he doesn't move at all for the entire round.

Also, keeping armed traps inside his bag? Does he not see any other potential flaw in that?