Without trying to put a spanner (wrench) in the works... After testing this, I was reminded of this issue / idea:
My issue is where we are mapping contiguous 'sections' and being able to tell that it is not just a single line... (example in the forum post) This could occur here - all existing geometry (from repeats at least) shows as the same blue colour. I have a workaround when importing existing geometry as entities (a different stroke-color value based on odd-even number to give a segmented pattern), but I wonder how to deal with this on a device (creating new entities or within repeats) - could it be done the same way with a calculate field in the form definition (picking up on the repeat number being odd/even and applying a stroke-color value) and would Collect be able to pick that up when rendering?
Maybe something to think about later, and might be 'niche' enough to not worry about.