There is nothing better for picking up det than a set of
det cans. However, not only would you look fooking stupid driving round with those on all the time, its also a bit dangerous
I think the products most likely to suffer what you mention would be something like the
KnockLink, which judges det based on only one rev location. The Knocklite uses several locations, so would be less likely to give false readings (read the blurb).
They aren't infallible, but they are better than nothing at all. Also, don't think that getting an A/F meter on a wideband lambda will cover you. It'll tell you the A/F reading, but not if det is occurring...