This can refer to a few things, such as cliffhangers, like seeing a car clearly drive off a cliff at the end of one story, for in the next story the driver to have quickly opened the door and rolled to safety - you just didn't see that part! It happens so often that "Life-Model Decoys" are a regular feature in Marvel as an excuse for someone suddenly being alive after you surely saw their head blown off.
"Oh that? Well, I knew I was in danger so I put that robot that really looked like me there and went and hid in the bushes for a while,"I say it is one of the greatest and weakest things about comics but really flexibility in the medium can only be a strength whereas weakness is introduced by the writers themselves. J Michael Straczynki (JMS) has often been criticised of poor characterisation he writes characters as inconsistent or not making sense because he needs something to happen to progress the plot (he's not all bad - I enjoyed Thor when he JMS dropped Asgard into Oklahoma). This was quite evident in Superman: Earth One, which I review here. However, without this flexibility, when a writer did something rubbish, we'd be stuck with it for ever. It might seem silly when people come back from the dead, were really robots/clones/from another dimension, or infected by an alien plant/rock/magic ring that made them act funny, but it really helps with housekeeping sometimes. Thankfully, this seems to be happening with Superman right now.
Grounded is a Superman story, by JMS, in which Superman decides to walk across America, reconnecting with the common man. The story, which takes place from issue #701 onwards, has been severely criticised. It is actually Comics Alliance's worst comic of 2010, which is really saying something. Although the starting premise is interesting and has the potential for an exploration of the human condition not usually affording by superhero comics, Superman basically acts like a complete dick the whole way through. Hopefully all that is about to change! JMS only wrote four issues of the planned 12 before leaving the series, which has now been taken over by Chris Roberson. The change is marked by the covers and you can't help but think it's a response to fan criticism.
So how's Chris Roberson going to do it? How's he going to spin the train wreck into a piece of modern art? Roberson has been brought in to finish the story based on JMS' notes but that still gives him some flexibility. Sure, Superman still acts like a dick in this issue but what's really important to realise is that it's made clear that he's being a dick and out of character to the point where Lois angrily accuses him of being turned evil by Red Kryptonite and then this happens:
It's the kookiness of comics that accommodates these crazy literary mechanisms and sets stories back on track. And this is why The Comics Switcheroo is The Great Comics Switcheroo.