From what I have researched they do not have the authority unless you have stolen or fake tags.

http://www.lto.gov.ph/Issuances/RA4136.pdf

CA rules LTO cannot confiscate license plates | The Manila Bulletin Newspaper Online

For instance a PNB officer tries to say your scooter is to loud because you have a after market pipe, even though it's the stock unit and he wants to rev your engine up as high as it can go while it's on the center stand to prove his point so he can confiscate your vehicle. Typical shakedown.

So who has the actually law about confiscating a vehicles tag or the vehicle itself for a traffic violation. I already know

"Only LTO deputized agents can confiscate driver's licenses and apprehend motor vehicles violating provisions of Republic Act 4136. Even the police must be deputized before they can implement that law,
Nothing in RA 4136 about taking tags or confiscating a scooter or car.