IOI's is just another thing to think about! I'd rather do away with them.

Also, surely IOI's just gives the girl power she doesn't deserve? When I'm talking to a girl, I don't want to spend my time looking at her thinking "Did she just touch her hair? Did she laugh? Does she like me? Do I need to do more to make her like me?"

I'd just plough on until you're stopped. If she's still talking to you, that's all the IOI you need. If she walks away - then you know she wasn't giving any IOIs, and move onto the next one!!