Underground trains do (almost) always stop at every station on the line. I wonder whether the issue in this case was due to weekend closures - there are very often lines and stations which are closed at the weekend, either for maintenance or because they're mainly used by commuters.
Well, out of two days i've visited London i had the pleasure to walk one station (and because of the elevator being overrun by people, i took the stairs.. the thing i've learned was that the London underground can be quite deep in the ground, it felt like kilometers :P ).
Taking the stairs is a mistake you only make once :)
There's a very strongly worded sign at Covent Garden station, telling people that it really is faster to wait for a lift. But I often see tourists making their way up the stairs.
Haha, yes. I've seen such a sign ("Emergency stairs, don't use!") but well.. it was soo crowded and so many people took the stairs i thought it may be a good idea (at first) :)
I completely misunderstood what you were saying. Please see my edit.
[1] actually not always, but with very rare exception.
{EDIT:
I'm getting downvoted so I think I misunderstood what you were saying.
On rereading again I now think you were saying "unusually due to overcrowding the trains were missing out every other station". Previously, I thought you meant "unusually due to overcrowding the trains stopped as frequently as every other station [whereas usually they visit fewer stations than that]".
I was trying to point out that stopping often is usual Underground behavior, thinking that you were assuming it wasn't.
}