Haha if we had more kids on the street (our street is mostly old farts) my 3.5yo would do that. She's shockingly independent, the worst she's done is leave a crowded restaurant on an extremely busy street while everyone was getting up to leave (very big birthday gathering) and took herself back to the car parked a few blocks away in a strange city. Noone noticed her leave. Fortunately a passer by noticed the small child on the tramline in the middle of the very busy road (Jetty Rd Glenelg on a Saturday night, for the Adelaide people) and rescued her. She was 2.5 at the time.

She tries similar things fairly often, we constantly lose her because we're talking to ourselves about going shopping or something and she overhears, goes out, unlocks the car, and sits expectantly in it (and then gets bored and fiddles with all the buttons in the car). She's made mention of really wanting to go to childcare a few times and I'm dreading the day she decides she's just going to up and walk there herself, it is a good 6 blocks away on the other side of several busy roads and a train line.

My eldest is the reverse, she's very lacking on initiative and will ask to do the simplest things (but won't ask things she needs help with or permission for) and it drives me insane. I think I'd prefer kids somewhere in between.