Bug fix for 'enq: HW - contention'

In our RAC production environment(11.2.0.4 on linux) we are noticing performance issues and cause is 'enq: HW - contention' . During the MOS investigation , we found that this was a bug(6376915) which is fixed in 11.2.0.1 but it is not activated until we turned it on by explicit event and bounce the instance. So we have to do following :

SQL> shutdown immediate ;

SQL> startup nomount;

SQL> ALTER SYSTEM SET EVENT='44951 TRACE NAME CONTEXT FOREVER, LEVEL 1024'   scope=spfile;

SQL> alter database mount;

SQL> alter database open;

Question 1 : Is there any risk involved by this 'alter system' command  ?

Question 2 : Although our system is covered by RMAN backup but is there any other safeguard that needs to be taken (to revert back the effect of above -alter system)  just to be doubly sure.