This is more likely to work because it actually breaks your driver. You're guaranteed to notice! And it makes it very easy to unbreak the driver so you're not utterly screwed when it happens to you.
Agreed, emitting deprecation warnings into the kernel log is equivalent to doing nothing. Who reads the entire kernel log anymore? And dumping warnings into feature-removal-schedule.txt is just as bad since nobody reads that either. Maybe these techniques should be deprecated themselves. :(