Can I make a mirror on PET plastic using Tollen's reaction?
I found a video on YouTube making a mirror on PET bottles.

Just that it consumes quite a lot of substance, and is not using Tollens reagent. My question is specifically about Tollens reagent. 

What she uses is some "secret mixture" called RA-205. 

It just proves that Ag can precipitate on PET bottles, which further supports the fact that will work with Tollens reagent. I'm will edit this answer once I execute my experiment, so this finding may only be somewhat helpful.