Just thought I'd share my experience with Samsung Galaxy Note (I) here since it involves both N900 and Note:

Not that long ago, a friend of mine wanted me to share a large file with him. It was too large for Bluetooth and I try not to connect the USB cabel to my N900 (I want it to last longer), so the obvious solution was to take my 32GB MicroSD out and put it in his Galaxy Note. Guess what happened, Note didn't see anything on the card, just a DCIM folder. A PC we put it in couldn't see anything either and the N900 as well.

So, long story short, Note (unmodded, with stock ROM) formatted my card without asking.

Isn't it nice when a device/operating system thinks it knows just right what you want to do?

PS: I was able to recover all the data in some form, but it was real pain in the a**, so let this be an example of what to be aware of.