Nothing to worry about from the Saudis at least - they are trained as an internal security force, and are incapable of acting externally without being cut to pieces. Worse, if the Saudis do sent them, then there are huge holes in its own internal security, leaving the entire country at risk.
http://www.veteranstoday.com/2016/02/06/iran-150000-saudi-mercenaries-ready-to-enter-syria/