It depends.  SLA and SaaS Agreement attornies certainly exist to protect both the customer and the provider itself.  However, SLA lawyers are much more frequently hired by providers than clients, as the providers will want to ensure that they’ll be protected from the financial responsibility of a lawsuit if a customer error results in a security breach, etc.  Some enterprise-level corporations may also wish to hire an attorney to look over the language of the SLA before they choose to sign it.  In most cases, however, the company purchasing the SaaS will not hire an attorney.