Laptops are a common client platform and many users will be running the ThinLinc client in full screen mode. This can make it difficult for the user to keep an eye on the current battery status and may not notice the problem until the machine shuts down or suspends.
Modern desktop environments usually have some form of battery indicator. It would be nice if we could integrate with that. Not sure how feasible it is though as it is likely designed with the principle of it being a system status rather than a per user status.