Ignition switch wouldn't cause the key getting stuck, so replacing the switch wouldn't do anything. Ignition housing or cylinder, yes.
A squeaky HVAC fan is a completely different kind of complaint. Your fan squeaks, regardless if they can duplicate it, the fan assembly is the only part that can cause that problem. Your key being stuck can be several things, worn key, bad cylinder, bad housing, gear shift assembly, solenoid, wiring problem. When you can't duplicate the problem you can't diagnose the problem. Throwing parts at the car only costs the dealer money and their customer thinking they can't fix their car. Some people are extremely anal with their warranty complaints, and probably 10-20% only happen if once a month when you're going turning into Walmart on a sunny day.
If it's a huge deal with you, leave it with them and let someone drive it until it happens.