Ani
Hello, and thank you for your message. I understand your concern regarding licensing and your collaboration with your customers.
When your customer uses Spine runtimes, they are utilizing part of our technology, which requires ongoing maintenance and updates. While your work as an animator might be complete, the runtimes remain an integral part of their project, and they may require support in the future. This is why we ask customers using our runtimes to have a valid license—it ensures they receive the updates and support they might need.
Consider also that if your customer is not eligible for an enterprise license, they might only need an Essential license, which is quite affordable.
That said, if your customer does not wish to use Spine as part of their workflow, you have the option to provide them with traditional frame-by-frame animation exports. They can then animate these within Unity or another platform of their choice. In this scenario, since our runtimes would not be involved, your customer would not need to obtain a Spine license.