By voting with their feet, the people of Hong Kong are sending Mainland China a pointed message.

The message amounts to an expression of little confidence in Beijing's vows not to be repressive when British rule of Hong Kong is ended in 1997 and the Chinese take over.It's easy to understand such trepidation. As Scripps Howard News Service reports, Beijing has just issued a draft constitution giving it power to veto all legislation passed by Hong Kong's lawmakers. This provision, as one critic notes, would leave the post-British legislature "unable to exercise sufficient checks and balances."

No wonder that more and more residents of Hong Kong are applying for visas, particularly for immigration to Canada and Australia. The exodus ought to worry the Chinese because it includes a substantial portion of Hong Kong's most capable people.

One survey shows that more than half of the emigrants are professionals, technicians, and managers. Most are in their 30's, and more than 75 percent have a college or university education.

Though the exodus amounts to only 3 percent of Hong Kong's population, it has increased more than two and a half times since 1986 and seems bound to escalate even more steeply as 1997 approaches.

If China wants to stop this costly brain drain, it will send Hong Kong a message of its own by assuring these productive people of the freedom necessary to keep them.