If you encourage a family member to take a genealogy DNA test, do you warn them of the potential to uncover family secrets of which they may be unaware?
You may encourage your father’s brother’s child to take a test to help with your (and his) paternal ancestry. The test results may cause them to discover things about their mother’s family that they did not know at all and that you, not being related to the mother’s family, had no idea about either.
You may discover that this first cousin of yours is not your first cousin at all.
I’m not saying not to have those relatives test. But make them aware that the test could potentially result in discoveries of secrets that their parents, grandparents, aunts, uncles, etc. thought had been taken to their grave. Some may welcome such discoveries and new family members. Others may not.