London - Any 20-stone prop hoping to disguise himself as a rugby sevens speedster in a bid to secure a switch of nationalities for the 15-man game should think again after the sport's governing body said on Monday it will be alert to such underhand dealings.
The International Rugby Board (IRB) says it is confident it will sniff out any dubious attempts to use Olympic sevens qualification matches to secure a shift in nationalities for the 15-man game - and that their system has the full backing of the IOC.
After a spate of border-hopping around the time of the 1999 World Cup, the IRB introduced rules that basically prevented anyone playing for a second country if they had already been capped for another.
However, with rugby sevens due to make its Olympic debut in Rio de Janeiro in 2016, the IRB had to amend their rules to come into line with the softer, passport-based stance of the IOC (International Olympic Committee).
The IRB and IOC consider the change to apply only to sevens but, in something of a potential loophole, it appears that a player who earned a switch in nationality via an Olympic sevens qualifying event would subsequently be technically allowed to also represent his adopted nation in the 15-a-side game.
The issue has been brought into sharp relief by the announcement of the French rugby union that they have a list of 10 foreign players who might be brought into their squad, including former England flanker Steffon Armitage, who has been plying his trade with great success in Toulon for the past three years.
Armitage, who won five England caps between 2009 and 2010, and was last season named European player of the year after helping Toulon win the Heineken Cup and French league title, has been overlooked for England selection due to Rugby Football Union rules that say overseas-based players will be selected only in extraordinary circumstances.
France coach Philippe Saint-Andre said last week that Armitage, and others, were in the process of applying for a French passport, which would open the door for a France call-up via the sevens route.
IRB chief executive Brett Gosper accepts that the rules appear to allow any player to switch but said only players with bona-fide sevens credentials would get the go-ahead to switch.
"We had to change our rules to comply with the Olympic Charter but we are reasonably sure that the spirit of the law - which is to qualify people for the Olympics - will be upheld," Gosper told reporters in London on Monday.
"The IOC are happy for us to have a qualification process for the Olympics, which is not under question. Where it becomes more controversial is the knock-on for 15s.
"Of course there will be discussion around that but we want to be sure that the spirit is being upheld. I think the regulations committee will be wary of activity which looks as if it is to qualify people for 15s."
France may have shot themselves in the foot by announcing publicly their ambition to bring Armitage into the 15-man fold - especially as his sevens experience is negligible.
Other situations might not be so clear cut, especially with some major rugby countries still not clear on whether they are going to stick with their established sevens teams for the Olympics or draft in a few heavy-hitters from the 15s.
However, it is not an issue that is overly-taxing the IRB a year out from the rugby World Cup and two years from what they consider a hugely important Olympic sevens debut in Rio.
"We are talking about a very small number of potential cases," an IRB spokesperson said.
"Many federations have government and national Olympic Committee support for their sevens programmes because it is now an Olympic sport and I wouldn't think they would want to jeopardise that."