If I have a 'no' position at .99, it shouldn't cost me any additional money to place a 'no' position on a second contract in the same market when only one 'yes' is possible in that market because my risk actually goes down as I add more 'no' predictions.
InTrade had this feature.
Correct. This feature is being introduced on the PredictIt trading platform. Check your email box for the announcement regarding Linked Contract Pricing to find out more details.