Are there other sites forbidding SQL developer to use c style comments?
I never use C-style comments in SQL code.  First off, Management Studio gives a very easy way to comment out blocks of code with SQL-style commenting, and just as easy to uncomment it out.

And not to mention if another person opens a SQL script file not in SSMS, C-style comments have a tendency to be elusive and the commented out code doesn't look so commented.

Just my opinion, but I stay away from C-style commenting.  No gain.