Normally you would want to switch the live (=hot) wire, leaving the neutral unaffected. Now normally brown is live and blue is neutral - until you insert your two-pronged power plug the other way around. Then blue is live and brown is neutral.
For your suggested way: actually I don't expect you'd get an explosion and a fire. Maybe a good spark, but immediately after your circuit breaker should come in play and protect you from further damage. Don't try this out, it's generally a bad thing when a circuit breaker trips.
The safest is a ready-made set of switched sockets as linked to in #1. Safe, convenient, looks good, and it's not expensive at all (especially considering it's Adafruit).