It doesn't really work that way on iOS. Developers have to use Core Location to access GPS. It sounds like ESRI are possibly using the wrong setting (they need be using CLActivityTypeOtherNavigation to avoid the issue). It is possible to tap into the raw GPS data if connecting to an external bluetooth receiver, I'd be curious to see if the road snapping still occurs when using something like an EOS Arrow or Bad Elf
I can't say I've encountered this phenomena in any of the apps we've created, although our higher-speed data collection is generally happening in areas that are nowhere near any roads.