In addition to watches with calculator support, even smartwatches and other gadgets will be banned from usage for exams lest it attracts technical cheaters or something which is kind of a good move. Google, Apple and other companies should have gotten aware of this flaw and especially for smaller devices that can be attachable to something that forms a watch like the Ipod Nano with something that forms that for instance. There's one thing schools forget, the smartbands, because they're freaking gadgets as well.
Unfortunately, certain smartwatches are trying to be disguised as normal watches which can pose difficulties for the invilgilators as if all kinds of watches should be banned. The workaround for that more clocks will be placed on the walls of the exam rooms in case you need to know what time is it while you're taking exams. Even worse is that there may be halls used for examination as well that there should be additional LED displays for time in addition to traditional clocks as the halls are really big compared to small exam rooms in which the clocks can be seen easily.
So after knowing this kind of news, you should know that smartwatches are not allowed in the exam centers probably due to the fact that certain kinds of communications may be transmitted such as pictures, videos, mails, messages and other stuffs that look like technical communications.