In the "more practical" department, consider this:
1. Put cameras in known locations on field
2. Robots have markers attached.
You get the idea.
3. FMS calculates position estimates for each target and delivers them each cycle to the driver station.
4. In order to make it clear that the FMS position estimates are best efforts, matches are randomly selected to have the position estimates disabled. This forces teams to have a workable strategy in case there are issues with the position estimates.