Not as good as the other tips, but if you press the boot unlock button on the remote, it doesn't unlock the doors, but as soon as you close the boot again it locks it automatically.
It's a really handy feature actually. Lock car, unlock just boot, put keys away, remove heavy shopping, close boot lid, hooray - no need to get keys out again to lock car! However, what I don't get is why the sodding hell you need to hold it in for two seconds before it works? Why can't it just open on one press?
I turned on the engine to demist the screen. I got out of the car (with no shoes on) and went to get into the boot for a change of clothes. The boot wouldn't open. Neither would any of the other doors.
That's really unfortunate! I wonder how that worked, though - my car doesn't 'autolock' until I drive over about 5mph. I would have thought that if you open a door manually (from the inside), it shouldn't then take it upon itself to lock it!
On the subject of cool tips: if you engage first gear but keep the clutch down, then floor the accelerator, the car will limit itself to 3k RPM, enabling you to have a quick but controlled getaway! (Dunno if this is a ESP, traction control, rev limiter or "launch control" thing but it's quite handy).