Hi all
Sorry for the delay in my response after starting this thread, it was a long weekend over here.
Jurgen has already DM-ed me stating that:-
- this invisible rating is a known area for points cheating
- there is a log in the gamification system to find out who made the invisible ratings, however it is complicated to retrieve and review 
- with 1DX just round the corner, it is unlikely that this behavior will be changed
I'm glad to know that my concern is also shared by others here. I still do not agree with the so called "reason" for having anonymity for ratings due to potential unfavorable ratings, especially as others have mentioned that this is a professional forum. Having transparency for every action taken will encourage everyone to be wiser (hopefully) as each and every action taken or word spoken/written reflects upon oneself professionally.
As a matter of fact, I think the gamification element to the rating system itself is inconsistent. It is only possible to award points for 4-5 stars but no point reduction on low star ratings. Firstly, there is already another mechanism to award points for good content, which is to "Like". Subsequently, apart from gaining points for 4-5 star ratings, I'm not sure if there are other benefits to the rating system, i.e. is it used in the backend to bring to surface higher rated contents during search? As a comparison, the rating system in StackOverflow, helps push up answers that are useful.
Anyway, I sure hope the 1DX system will not have similar loopholes (not sure how it's gonna work on that platform.)
Rgds
Eng Swee