E.C.
Hi K.:
FWIW I had one of those folding seats and one day one of my girls felt a little "pinched" by one of the folds and didn't want to use it after that. I ended up bringing the padded toilet seat insert in a plastic bag in my backpack - kind of a pain, but she was comfortable using it and I figured it was worth the extra peace of mind (I know some moms are able to hold their LO's so they don't fear falling in a public toilet seat and more power to them, but it was easier for me to bring the seat insert and set her down on it!). I'd put one of those paper seat covers over the big toilet seat before putting the insert in, so she wouldn't touch the toilet seat itself
As for the pullups - what I did was put the pull-up *over* the regular underwear for naps and when we went out on errands - that way she still had the underwear on and felt the underwear instead of a pullup, but if she had an "oops", I just had to change the underwear and not the whole outfit :-). You pretty much know when you can stop putting the pullups over the underwear when you realize she's not "oopsing" any more :-)