Originally posted by darthgoober
That would depend on the weakness though. He might not sense that he can one shot someone via hitting them in a specific place, but something like a vulnerability to a particular form of radiation... sure it would(he's demonstrated as much against the Hulk and Gladiator). Whether or not he'll chooses to capitalize on it is another matter, but in forum fights characters fight smart so he'll use the ability every time just as Supes will try to blitz the Hulk every time.
The Surfer just sensed the Gamma energy/rads within the Hulk and used his powers to take advantage, his cosmic senses were definitely at work there, but it wasn't him sensing his weakness, it was the Surfer sensing the Hulk's energies and being smart. As for the instance with GLADS, there is nothing to suggest he didn't just have prior knowledge of Kallark's weakness, as opposed to him using his senses to find this weakness of his. All that is merely assumption on your part.