The police in the border region in both countries is currently being trained for patrolling in the other country (there are some differences in legislation and operational procedures). So not just pass-through but actual law enforcement work.
After WW II, when Finnish Lapland's roads were largely destroyed by retreating Germans, Finns used the roads on the Swedish side of the river to get up north. Today it is perhaps the other way round; the Finnish side has more population and the roads up river are bigger so it might be feasible for the Swedish to use Finnish roads even if the destination is again across river on Swedish side.
SWAT teams no, not without urgent need and/or official request, and people would rise eyebrows also for SWAT teams driving around in their own country for no reason.
After WW II, when Finnish Lapland's roads were largely destroyed by retreating Germans, Finns used the roads on the Swedish side of the river to get up north. Today it is perhaps the other way round; the Finnish side has more population and the roads up river are bigger so it might be feasible for the Swedish to use Finnish roads even if the destination is again across river on Swedish side.
SWAT teams no, not without urgent need and/or official request, and people would rise eyebrows also for SWAT teams driving around in their own country for no reason.