[lukan]

"Not keeping it on their side" ... well. If they sequenced it, they have data in their computer, right? How could you avoid that? I don't see this as possible, it depends on trust"

First it depends on the contract, if it states they have the right, then they can and will legally use it.

If the contract would say no - then they would have a much harder time making use of that data, as it would be illegal.