agreed.

the advantage of removal however is that if there's a bad mechanical
connection, which i guess is possible, you'll remake it on
reinstallation, and hopefully make sure it's good.  it also depends on
the sensor head's physical connection point.  if it's screwed through
the block to touch the wet liner, the outside tapping thing may not be
that effective.

last thing: haynes recommend tapping the sensor directly with a hammer?
 geeze, those people need their heads tapping with a hammer.  if ever i
needed reminding why haynes manuals are to be avoided...