I also had two with the BSOD, an early 2012 MBA and a mid-2013 MBA.
Both would crash whilst in a bag during my commute, no magnets.
The 2013 MBA went on to crash at random whilst working, no magnets. It even crashed mid-presentation whilst operated by remote control, so no physical proximity or intervention.
I too have been able to walk into Mac retailers and crash every MBA I was allowed to touch - they weren't happy with a public display of their fallibility and soon asked me to stop. Still no magnets.
The latest available version of Mavericks (10.9.2, 10.9.3 is for developers only) has partially resolved the issue by changing the behaviour of the power button so it eliminated one type of BSOD but replaced it with another.
The screen now freezes, without going black and has to be reset.
Of the 39 people who responded to the survey on the public Fac ebook group, 7 still have the original BSOD and 5 have the new type of failure, neither of which is recognised as a crash and both require a hard reset.
Conclusion: Apple still don't have a clue.