The suspected underworld figure was turned back to the UK by US authorities after a tip-off from law enforcement in Scotland, the latest in a series of what officers call "legally audacious" disruption tactics.
Brian McConnachie, QC, chairman of the Faculty of Advocates' Criminal Bar Association, said: "If the Crown has the evidence to prosecute a gangster then that is what they should be doing, rather than routinely trying to disrupt their lives. It all seems to be a bit Big Brother to me."
Former senior prosecutor Mr McConnachie and other defence lawyers fear people's lives could be disrupted by such actions without the involvement of a court - unlike when alleged criminals face prosecution or civil actions under proceeds of crime legislation.
Another QC, Gordon Jackson, last night said: "It all depends on the quality of the information being provided - and that it is not just gossip and innuendo."
Scottish police were backed by prosecutors when they tipped off the Americans about the Scottish gangster, who has not been named and is currently subject to an investigation.
One law enforcement source last night defended the tactic, saying: "You'd hope the Americans would tell us if one of their mobsters was getting on a plane to Glasgow." US immigration officials have discretion on who to allow in to their country.
Detective Chief Inspector Paul Donaldson, of Police Scotland's Specialist Crime Division, said: "We will use all available tactics to disrupt the activities of those involved in organised crime.
"The successful use of tactics will often require the sharing of intelligence between law enforcement agencies within the UK and beyond."