If Delta allowed the connection to be booked the bags will make the connection the vast majority of the time. If the bags missconnect the cost of delivery the bags removes all profit from your ticket and pushes it to a loss. They don’t like losing money. If the bag does miss the connection you should be able to arrange in SJU to have it put on a later IC flight. The Delta app has a bag tracking feature that is excellent at reducing anxiety. You can help the process by having your bag clearly marked with your address and phone contact number. Make sure it’s your cell not home phone. In addition place a sheet of paper inside the bag on top with your travel/contact info including charter company. They have machines that excel at ripping external bag tags off! They are pretty good at getting the handles also!
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