My wife is flying this weekend and got a note from her doctor disclosing a knee replacement (so the TSA won't take her knee apart). She also has metal plates in her neck and lower back. I didn't believe her when she said the detectors won't go off with titanium, but, would with her stainless steel knee. So, I got my Pro Pointer out and sure enough, the knee sounds off, but, her neck and back didn't! I didn't try the F75, however, suspect since the PP didn't sound off, the F75 wouldn't either. Just doesn't make sense to me........I thought it would respond to any metallic object!
get out there and dig those foil signals.