I'm not sure I know what to make of this advice:
Rainboe, check Part A, 8.3.2.6.1
"Preflight checks on all flights, HF radios are to be tuned....etc.
Most planes I have ever flown have selcal armed and ready to go and no ability to switch off. It doesn't matter what you tune your HF to, you can still have a spurious warning. If tuning ensured that you would not have a spurious alert, I could understand the advice!