My thinking is that I can match a profile, but the profile may be wrong. If the sources are only other family trees, isn't it possible to perpetuate errors by matching?
For example, many family trees may show that John Smith's spouse is Mary (Jones) Smith, but there is no evidence for / record of this relationship. Yet people see this in someone's family tree, assume it's correct, and copy it to their tree. Unfortunately this is what I did when I first started, until I realized how many errors are in many family trees.
Bottom line, in bringing in profiles from a GEDCOM file, will I have a chance to select which profiles I bring in, so I can keep only those with reliable sources, or do I have to keep them all?