Would slave owners really get people to chase runaway slaves all the way until they got to Canada?
Many of the “free states” had laws that stated they would return runaway slaves. Just because a slave made it north of the Mason Dixon line didn’t mean he was free…. which is why many of them had to keep going and cross into Canada so they would be beyond state laws. There were MANY people in the “free states” who had no problem with slavery. Returning run away slaves was the “political compromise” they came up with.