There is nothing more disconcerting than seeing a driver/rider, looking down at a prat nav, trying to punch in new destinations etc whilst following you down the road; other than, of course, them being in front of you.
Yes, you can slow, put more space between you and them but can you honestly say that you know what they are going to do?
I've had drivers/riders swerving back n forth across the road, also deciding that the junction they have, more or less, just passed was where they wanted to be stopping dead (cos they are incapable of thinking, I will carry on forward until I can find somewhere to turn around ie. another junction or roundabout) or worse still trying to make the junction by going in the wrong side of the road into oncoming traffic!
SMIDSY just doesn't help and is the worst thing you can say to anyone but especially to a biker. However, a biker using a prat nav and not concentrating on the road ahead and around him/her saying it to another road user once they have ridden into them or knocked a child down et al is worse and hypocritical at best.
We have all been on the end of that one and tbh, although I don't ride, I would be appalled to on the back of a bike where the rider said it.
For goodness sake put the destination in the prat nav BEFORE you get on the bike. If you need to reset, PULL OVER & STOP before you do so. It isn't rocket science.
**Steps off soap box**