I lost my mew wallet about a month ago. I don't know how it happened to me but yep, I lost it. I think, own wireless internet is not safe too. Public wireless are always watching by hackers. There is only one way to keep kalm, it is your mobile phone...
I have known someone who did not lost her MEE wallet but lost coins inside her wallet that was strange because she only log in her wallet once and check the balance in ethplorer everytime but upon checking just this week one of her coin is missing and she did not tranfer anything. Hackers now are indeed intelligent we do not know when they will attack so better yet transfer our investments in a more secure wallet.