how to determine which wrist the device is worn on?

I've never seen a way to get this info with CIQ.

Too bad but thanks for answer

If an extremal HRM is used, you can't even say for sure if the watch is being worn, or if it's inside the swim cap for better GPS.

Moving this to the developer discussion forum.

You should be able to work out from the 3 axis accelerometer data I’d think.

I can but it will consume (potentially double) a lot of resources which I save for stroke/swim style recognition algorithms and it will come with <100% accuracy resulting in even lower accuracy of stroke recognition (which hand?  Then: which stroke/swimstyle?). 

I would simply add a setting for this and take all guess work out of it,  The wrist someone wears a watch on tends to be pretty static and there are even some Garmins, where during setup you specify the wrist you use.  You just can't get that info with CIQ

I wouldn’t think it would, as clearly one axis will be inverted. But you’ll need to do some tests analyse the data to be sure, before you do too much.

There are many time you will need to help educate users.