OK, I can speak on this subject with some authority!
Last year my (ahem) "friend" bought 1000 single dinar coins very cheaply on ebay. They weighed an absolute ton! He very carefully wrapped them in paper in 50 dinar "tubes" and stuck 10 tubes in the bottom of each of his and his wife's suitcases.
On arrival at Monastir Airport only one of the cases arrived on the conveyor belt. The weight in the bottom of the case meant that the case arrived bolt upright on the conveyor! My "friend" suggested that his wife took that case and waited in the arrivals for him. After some 45 minutes all of the people had got their cases and left, all except my "friend".
He approached customs to ask where his case was and he was told it was coming soon. After another 15 minutes the case appeared on the conveyor. Bolt uptright! Two uniformed policemen casually followed the case at a discreet distance. My "friend" removed the case and headed for the door with a cheery demeanor, right up to the point when customs asked if they could have a word.
They asked if he had a key to open the suitcase, to which he replied that the case wasn't locked. They asked "him" to open the case and to "his" horror some of the carefully wrapped tubes had split open and there was loose dinars everywhere! "What are these?" the official asked.
At this point my "friend" explained that these dinars were being brought home (at his expense) so that they could find their rightful place in the Tunisian economy. It would be fair to say that the official was less than pleased! He explained that they x-ray all cases on arrival and that this one had shown up as suspicious. After a few stern words about how illegal it is to repatriate dinars my "friend" was sent on his way. When he got to the hotel he counted all the dinars to see how many they had taken and (unbelievably) every single one was still there!
Would I recommend that anyone else tries this? Absolutely not. My friend aged 10 years at that airport........