I have a bandless GW60 , ( who hasn't )
It now lives in my pocket.
My questions are :
1 , how accurate is the watch in my pocket and if readings are out , will or won't it be in my favour.?
2 , I've bought a stretchy wrist sweat band with a zippered pocket to hold key cards . $12 eBay . Would this be a better option for accuracy .?
I've heard if you wear it under a wetsuit it is less accurate , What exactly does that mean . Would it read under or over speed . Or is it more of a alpha thing ? If it would read under that would be OK but if it reads over , that's like cheating.

Put it in a pouch or bag on your arm or helmet with the antenna facing the sky.

1. It's not all about accuracy. The most likely scenario is that you will miss large chunks of your session or runs when the gps cant see more than 4 satellites. This happens pretty easily in a low statellite visibility situation which can happen regularly when there are only 5 or 6 GPS sats even available for a time period. The GW-60 wont record data if it has less than 5 sats in lock. (As an aside, If you have a device like many of the sports GPS watches that do not respect this strategy, you will get VERY inaccurate data when it is only locked onto 3 or 4 satellites, and since most don't record the satellite count data, you won't even know when they are severely compromised). Error values go very high when satellites locks are constantly changing due to poor sky view - this can easily happen when your body is blocking the view of a large propotion of the sky as you turn or you body orientation shifts. Chunks of data points are also often lost during the switch in sats.

2 sounds promising. Put it on your bicep.

As said above, blocked or weak satellite signals will seriously affect your data. It can be gaps or spikes of junk numbers. Error values can go sky high, meaning that you data is very unreliable and that can be either high or low. Filters in good analysis software should catch that with GW-60 data, but you might miss out on some of your best runs.
Alphas can be effected much more because if the probable rapid change in satellites in view caused by body blocking, causing high error or loss of points during and after the turn.

So it's the faraday cage effect. Anything conductive surrounding the device will act as a shield, the more conductive and complete the shield the less electro/magnetic stuff can penetrate. So wetsuit material holds a fair amount of salt water, which is conductive, so will act as a shield. If your pouch is nonabsorbent it may be ok. You can tell by the +/- data and the sat count. let it sit for several minutes, antenna up out of the pouch. Then put it in the saltwater wetted pouch in exactly the same position. Again leave for several minutes, then compare the data.
Poor data can go either way but if it's too poor the software filters will reject it and you won't have anything.

(beat me Andrew)

An example of a faraday cage is the aluminium can I keep my carkey in when I go for a sail. My new commodore has lock buttons on the door handles. If the car can sense the key then these buttons are active. I don't want to trust the expensive key to a pouch, so leave it in the faraday cage, then the lock buttons don't work