Maybe it's just me, but I have NEVER been able to trigger a trap with a summons. They and charmed monsters can dance on traps all day, but the moment one of the characters get close they get nailed. I recently installed the latest patch, so maybe this is fixed in my game. But I can't tell you how many times I tried to use the Wand of Useless Summons to send some gnolls out to die, and they just walk right over the stupid trap without triggering it.
I didn't know about Mirror Image and Minor Spell Deflection, though. Good to know, as I am planning to play another all-good party next, and Nalia will be my thief until Imoen gets rescued (yes, I can hear the groans already
). Has anyone ever been able to bash a chest? That's the other thing that I have never been able to do, even with strength belts. Chests in my game might as well be made of adamantium. But, like I stated, I did install the patch, so may be fixed now.