Only One; let's say she's not impressed.
You know why I carry a spare mag? Because I'm scared to death that if a situation goes completely to hell and I don't have a spare, I'll either get a jam and not have the fastest way to clear it or turn out to need a few rounds more and not have them.
About five months ago I watched a lady try out a Springfield 1911 in 9mm she'd borrowed from the rangemaster; pistol and mag both almost new. She loaded it, fired once and then stood there looking at the live round stovepiped in the ejection port. Cleared it(new shooter, did it slowly and carefully with her trainer), tried again, and when the slide cycled the next round in the mag shot up vertically and left her with an empty chamber; once it shot the first round up after the empty and the second stovepiped. The RM swore he'd shot the thing a few days before with no problems, but that mag was well and truly screwed now.
Lawdog writes on the subject here, including
One of the more disappointing, yet amusing, experiences in my little life was slapping a USA Inc magazine into a Smith and Wesson 5900-series and getting this gorgeous brass fountain out through the ejection port before I could hit the slide release.
And if that'd happened in a serious situation...
A spare magazine. Always. If you carry a revolver, a speedloader or speed strip or something.