Trust?

 There is an old story that I think has an element of truth about when Roman England was being overrun by Saxons.  The Saxons invited the leaders to a dinner to forge a friendship and weapons were prohibited.  The Saxons however hid knives in their boots and at a signal from their leader pulled them out and slaughtered their neighbors.  This act of treachery was an early indicator of who these invaders were.

We loo at this act of betrayal as a bad thing but it helped lead to a Germanic takeover of Britain and many here are proud to refer to their Anglo Saxon heritage.  

Things like this were not unique to Saxons, this world has been governed by a simple rule, might makes right.  You take what you can and leave what is well protected.  If you lived in those days your best option was to protect yourself by aligning with a powerful leader who others would not want to anger.

We tend to think the world is different now but is it?  Most of the world was in states of near constant warfare for much of history.  Humans are greedy and somewhat bloodthirsty.  You are on the strong side or you are at risk.  

So if your sworn enemies invite you to a feast as a gesture of friendship you might want to secure a weapon to protect yourself.