That's a great question! I can see the benefit of wanting to make sure that the suppliers are reliable. If you are selecting those from Oberlo Supply I just wanted to let you know that they are vetted before they join Oberlo.
Additionally, they sign a contract to make sure they fulfill orders in a specific number of days and respond to messages. Of course nothing is perfect but if there are issues at any point you can also email the Supply team in the app and they will step in to help. Hope that adds some insight!