Well, most of the questions have been answered then.
It's by no means a deal breaker. It just means that you have to do things differently. Using a transistor or Darlington array to do the switching will work just fine, as mentioned.
@Websteria -
Neither platform will allow a buzzer to buzz. They are microprocessors and as such, pretty low current devices. Anything more than an LED and you should use something else to switch it.
What I was talking about is driving sensors off digital pins. This allowed me to turn them on and off when I wanted which saves battery. Still doable now but I need an extra component. Like I said, not a biggie.
As an aside, if you do use something like a buzzer, please please please use a diode across it to stop any back EMF.
Even with something as low voltage as 1.5/3v? It seems the transistor should be able to stave off the EMF, if it were a relay then yes a diode is necessary... :-) Maybe I'm wrong.