Having had something to do with the Typhoon cockpit design several years ago, the Phase of Flight moding is associated with deployment of the gear. So, when the gear is selected down, the main displays (which are very prominent compared to previous FJ cockpits) change radically to indicate a phase change to landing PoF.
Now, I am not saying that it is true in this case, but is possible that pilots will tend to associate gear down with main display change whereas the only true sign (ie safety critical) is the gear indicator.
By the way, the very clever comment (not mine) regarding cheese holes lining up is a reference to James Reason's "Swiss Cheese" model of human failure - try Googling it, its very interesting. If you read his book, you will find that human failure (for whatever reason - no pun) is inevitable no matter what. Chernoble is an obvious example.
By the way, Typhoon has a triplex redundant Weight on Wheels indication certified to a failure rate of less than 10-6.