Want another interresting one, happened to me at christmas.
In holding above destination, airport closed due to weather below minimum (cat II).
Alternate scheduled, is a rather near airport but on the other side of the mountains ridge where weather is cavok.
Plenty of fuel aboard, so I am discussing with company mangement, who want us to hold as long as possible expecting the weather to improve which in my opinion is unlikely.
When...
ATC called us, alternate airport now closed, no parking position available anymore (due to the high number of diversion), what is your second alternate?
Here the alternate could still have been be used in emergency, the hell if I am stuck on the runway without parking in emergency, but that could as well have been: a guy IS stuck in the middle of the single runway!!
Happy to have fuel to go somewhere else much farther away....
Think about it before commiting yourself to ONE airport whatever it is your destination or alternate!!