I guess it depends on what field you're in and what state you're licensed in.
"Drawings , specifications and other documents prepared by [consultant] are the instruments of the consultant's service and shall remain the property of [consultant], whether or not the project for which they are intended is constructed. The drawings, specifications and other documents will not be used on any other projects, additions to this project and/or for completion of this project by others, except by agreement in writing and with appropriate compensation to [consultant]."
That's a fairly standard notice that appears on nearly every drawing we produce, and similar language can be found on many blueprints.
Part of being a PE/RA means you're responsible for what you design, beyond just being fired. It's unacceptable to let someone take your design and use if without your knowledge and supervision, because if they mess it up it's your ass (not just your company, you personally) that gets sued. To that end, some consultants choose to explicitly maintain the intellectual property rights of the design documents.
And it's explicitly against the law for anyone who isn't a PE/RA to modify documents prepared and sealed by a PE/RA.