The general idea of individual multipliers itself is not terrible, but the system needs some guardrails.
  1. There should be a distance limit with 2 components -
1st is if both people guess in the same ring, for example both people guess in the capital like Prague but its actually in Brno, just because one person was 1 mile closer that shouldn't give the other person a multi.
2nd is there should be an overall mileage limit, if both guess are over 500 miles away then no one should get a multi for that.
  1. Give one mulligan per game that stops the multi from increasing, everyone has a bad guess sometimes.