There are plenty of irresponsible shelters out there but a responsible adoption center will insist that you have interaction with the dog before you adopt. The will have done thorough behavior assessments and will do their best to make sure the dog suits your lifestyle. I would guess about 80% of the dogs at her shelter require no further training to be a pet. In the remaining cases potential adopters are given guidance before they adopt and will usually know what they're in for ahead of time.