[madars]

There are multiple attacks in that video. IP is one, but a much bigger one is knowing the real output (or maybe real output plus one other output) among 16 ring signature members. They do not explain how they achieved it but one could guess that maybe by just doing a lot of tx themselves - 15 decoys is just way too small and flooding blockchain with transactions all but ensures that someone picking random ring members will pick a lot of your outputs (and thus have little privacy from you). It is also for sure too small for targeted active attacks (e.g., it is not safe to have repeat interactions with the same entity), see https://www.youtube.com/watch?v=9s3EbSKDA3o You really want more than 16 ring members, preferably all outputs ever created like in Zcash. FCMP work promises to bring similar privacy to Monero but is years on the roadmap.