When starting with the consumption of cloud services, one of the risks often discussed is the vendor lock-in. Organizations see a risk in putting their data or applications in someone else his hands and not getting it back if trouble arises.
Vendor lock-in is a risk that should be looked at during the on-boarding of the new provider and many try to mitigate this risk by defining a clear contract. This contract often includes agreements when the customer wants to no longer make use of the services of the provider. How to get the data back, support of smooth migration away from the provider, etc.
But when you and the provider see each other as strategic partners, a contract is still needed, but trust is more important. If you don’t trust your provider and harass them with all sorts of contracts there is no trust or partnership and you should ask yourself if this is the strategic partner you want in the first place.