A few years back when flying with Swiss (BAe146) BHX/ZRH we boarded thru an airbridge and I took my seat ready for departure. Minutes later, looking out of the window, I observed that the wing was below me and without any engine(s) attached to it, "WTF" I thought and only upon checking the emergency card did I realise I was actually on board a Helvetic F100.
Another day I was supposedly travelling BHX/CDG on an AF/Cityjet BAe146, upon checking the emergency card I found myself on board a Blueline MD80 series.
Then, two years ago, booked on CX HKG/CEB on an A340, "great" I thought, nothing like 4 engines across water, upon taking my seat I took a look out of the window to count engines only to realise it was actually an A330.
But ... for my return trip CEB/HKG last year, which was actually supposed to be an A330, I was ready for them ... or so I thought, took a look out of the window and this, supposed, A330 had two engines on each wing.
The moral is that half the time the travelling public have no idea what they're flying on and tell them it's a B707 or a B787, many will just stare with a blank expression because it's merely numbers and all the same to them.