"I don't think it occurs to very little kids to fake illness,"
oh yes it can........DS2 did a very convincing impression of being knocked out unconscious on the hard stone floor at church while I was pg with DS3 (quite early on) so he was barely more than 3yrs old.
I was playing the organ, he was running up and down the aisle on the opposite side from me. Suddenly I looked up (about 5 minutes before service was due to start) and saw quite a few people crowded round and that I was being beckoned furiously. I rushed off and across to find him motionless on the floor. He'd apparently slip while running and they thought he'd knocked himself out.
After the initial panic I thought about other, similar (but not quite so dramatic) pieces of acting he'd done and I tickled him under the chin (where he's extremely ticklish). His mouth moved as he tried to stop himself laughing. I lifted him up on to my knee (with others saying "do you want us to call and ambulance.......and me saying no he's fine) and after another minute or so he opened his eyes.....absolutely fine, hadn't bumped himself at all and hadn't been knocked out!!!!!! He was just pretending - and as he knew more people were looking he kept it up longer!!!