When the first team searches McGarrett's office for bugs, they use a gamma radiation detector. Later, when Kimo and Truck search the office, they use a metal detector. Neither would detect a radio microphone.
When Alika has his goon, Johnny take the envelope with the bribe money that Kimo touched, both Alika and Johnny touch the envelope, leaving their fingerprints, When Johnny deposits the envelope in a safety deposit box, the envelope is now in a plastic bag.
Editing mistake: when Kimo and Guido are on the cliff, the image is vignetted in the corners. This appears and disappears with distance and close up shots.