[zoop]

In this case it's a defect, but in general, people operate their Macbook Pros with the lid closed attached to an external monitor.

[simias]

Makes sense, but I doubt many of them operate the built-in keyboard with the lid closed :). Ignoring the keyboard input in this case would be a cheap "fix".

[raverbashing]

Yes, but most crucially, they don't turn it on with the lid closed.

Open the lid, turn it on, closes the lid.

Should be fun to try to power an older MB with the lid closed to see what happens.