Re: Filth
My interpretation of the distinction is that it was intended for e.g. listening in on radio transmissions or splicing a probe into a fiber line. That is, if you have to compromise the premises of the defendant then it's in storage, but if your presence is only in places outside of their physical control then it's in transit. Sealing up an envelope and putting a stamp on it doesn't protect a letter from being taken by a search warrant for your house. It's not in transit until you drop in in the mail box.