They should be worried, Erdogan and ilk have given the Dutch lots to worry about over the recent years.
Intelligence Services worried about Paramilitary Turkish groups
The Dutch intelligence services are worried about the possible arrival of Turkish paramilitary groups who are active abroad and may come to the Netherlands. This is written in a report about terrorism in the Netherlands by the NCTV, (the body which deals with the fight against terrorism). One of the paramilitary groups has created a Dutch faction which possibly could be used for illegal actions against enemies of Erdogan abroad.