The training pants I have Imsy Vimsy are not very absorbent but they would keep a poo in. If a wee was done it would most likely drip onto the floor.

I have a nearly 3yo who is also almost fully TT. I mainly only use pull ups at night now. So far no accidents at the shops yet *touch wood*. He is quite good at giving me enough notice.... plus I make sure I just take him lots when we are out... if I see a vacant baby change room cubicle i routinely just "drive' the pram straight in.