its nothing to do with the server loads, as they would have restricted the amount of ip that can log in? if the anount becomes too heavy they would increase its capacity or you would get some kind of message saying Server is full plz try later.
Its my guess that once you have a lot of graphic movement in one area the load becomes too much and crashes out this will then produce a dump log and they then have to sift through it and weed out the problem?
This is all just speculation as i think if they want to bring the server down for maintenance then they would give us a few minutes and you would get some kind of on screen message saying the server is going off line in xx minutes.
its this way: theres a peak time, when everyone is playing, worldwide. thats around 17-21 gmt.
and thats always the time servers keep crashing. thats it. cryptic is just to stoic to react on this fact. setting up more, or better hardware. the game is fine all day long in europe, but @ 17-2 gmt ist impossible to play. after that its okay again. so it MUST be the peak time and cryptic is just unwilling to fix it.
its no unexpected downtime, its an predictable "un"expected downtime.