@MarkG For sure, every user has his own experience. In my personal experience the way I wear my watch is:
I wear my watch 24x7
Normally it’s weared like a normal watch
When I’ll take a workout I press it about 1 inch (2-3 cm) above my wrist bone and tighter than normal
Temperatures here are relatively mild (and I don’t go out for training if it’s colder than 5-7ºC) but cold enough to put a difference
Anyway, I never had your poor experience. I know someone who needed to depilate his wrist to let his watch take good data (with Suunto and with Polar), but as I told you, mine is pretty hairy and have no problems.
Coming back to multisport conversation, it’s like a pretty nightmare: Spartan Series (and S9) are multisport series just because:
have a triathlon mode (but limited to exactly just that)
you’ve got the option to change sport mode whenever you want (but hey! nobody said it must be easy!)
BTW, MC has a good point of view of the triathlon and multisport records, but it’s not still expected on SA.