I hacked a cheap WinCE-based Satnav and installed ScummVM onto it. Also, I made damn sure I didn't pay for my copy of Monkey Island... but I guess that's the pirate in me.
I half imagined the museum staff to march up to me and demand "Ihre papiere bitte!"Non-commercial sketching is permitted in the NMM galleries and grounds. Sketching refers only to pencil and charcoal drawings — no painting or pen drawings to be undertaken without prior permission from both Collections Services and Collections Group staff.
If it's worth doing, it's worth doing for money.