In the UK, Abu Hamza and Yaser al-Sirri,[1] Jim Davidson,[2] and the late Edward Heath[3] were described in media as having been subjected to this tactic.
Former friends of the late prime minister Edward Heath complained that Mike Veale, Chief Constable of Wiltshire Police, had mounted a 'fishing expedition' in an 'unsatisfactory and prejudicial' investigation costing £1.5 million which had turned up 'no convincing evidence' that Heath had ever sexually assaulted anyone, according to Lord Hunt of Wirral.
The looseness of the definition of relevant evidence is generally construed to mean "liberal" production.
The only constitutional limitation on the search by subpoena is that it not be hopelessly broad or severely burdensome.
The criticism expressed here is that the path from an insufficiently connected observation to actionable theory is held to be too long and therefore fruitless.