1.   I do not believe in block withholding because it does not make sense for the actor.  
2.  My assertion has always been effed up gear.   That assertion fits this scenario (and many others).   I suspect the people that effed up BTCguild and Bitminter likely lied that they did not sell gear to the public and many people have the same shit miners they were using.   MAYBE they fixed it with a small tweak to their software and maybe they sent that fix to all the people that bought their gear, and maybe they did not.    Having solo mined until size pushed us out, I can assure everyone that there is NO way someone with 2PH/s (7 weeks ago) was not solo mining.    That means the person KNEW his gear did not work but did not know why.   So, finding the solution 24 hours after Michael and wizkid called them out on it, seems very unlikely to me.     They likely just pointed other miners at elegies (miners they could have bought with days of mining income from these pools) to satisfy wizkid "that the software bug was small and see I can solve blocks now?"

3.   Multipool, take your scratch ticket analogy and shove it.   That is stupid.   How about this.   It is like one (very fat) member of the community eating every day but only contributing to the food budget one in 11 days when over time everyone must contribute equally (to their percentage of consumption).   Koi has NEVER gone that long without contributing.   So, why don't you shut up until you have hit a block EVERY day for 6 days and are on the other side of this luck curve.

TL DR: A.  MultiPool has gone thru some bad luck.   Luck like that happens about 1 in 11 times.    Multipool is due for some good luck.    Expect to see them banging a lot of blocks out in the next week.  
B.  Still believe someone is selling equipment that does not work.   Many people do not believe that because they have never seen anyone in bit coin (especially producers of miners) be incompetent or unethical (so this could never happen).
Largest argument against this is "the design is so simple, it is hard to fuck up".....    Left turns are easy to make to but I still see a lot of wrecks at stoplights.   Ask GM how simple an ignition switch is to design.