its good to know that there is a form of encryption. but marketing director for The Wi-Fi Alliance said:
"I just tell people not to do anything at a coffee shop that they wouldn't write on the back of a postcard," 
The details to log in to my microsoft account  (even in hashed form) are not something i would write on a postcard.
my question remains:  is there a way to stop this automatic login / and  the sync  of contacts& calendar?  i found the checkbox  to stop email sync. & photo sync, but not one for calendar or contacts.  
i think disabling this sort of syncing is the safest way to browse with unkown wifi hotspots. even if i unknowingly  connected to a hackers laptop masquerading as the cafe's wifi hotspot
if all i did was read the news and check the weather, he couldnt get any usable info off me. 
i thought of a solution & did a test. i went into email+accounts and changed by ms account password to xyz so it wouldnt be able to sync.  i powered phone off and on & it still synced!!. as soon as i touched a calender entry it instantly was updated on the live.com calendar!   what am i doing wrong here? 
thanks
all these articles , including this government one  says there is a risk  (this is not specific to windows, but i cant find where to disable syncing)
Tips for Using Public Wi-Fi Networks | OnGuard Online
Is It Safe To Bank On Public Wi-Fi? How Not To Get Hacked!
5 Traps: How do I use public Wi-Fi safely? - Red Tape