I use the built-in flash ALL THE TIME. It works great with the 03 for low-light selfie shots with multiple people (use the 2 sec. timer).
I just flick the switch and let the flash fly with no worries. I've done it hundreds of times. Sometimes when I'm just at my computer and my Q is at my desk, I just fiddle with it, and sometimes this means I just constantly pop the flash open and closed.
I have tried to use the flash to launch things on my desk while bored at work.
When I'm showing the Q off to people, I always say "WALL-E" in a really annoying robot voice as I'm opening the flash, and it sometimes makes people laugh (and sometimes they don't and I quickly change the subject).
In short: Don't worry!