Don't think there is but hopefully I'm missing something!
I'd like a user to be able to modify an asset on the fly, but keeping it unlocked has its own set of problems.

You can use hou.Node.allowEditingOfContents() to unlock an asset.

To complete the cycle you use hou.HDADefinition.updateFromNode() to save your asset, and hou.Node.matchCurrentDefinition() to lock it.

Many thanks