Did you find anything interesting? I started doing this recently and did not find anyone misusing my email so far and am now wondering if it's worth the extra effort.
For alias addresses they are filtering that because the data thiefs and middlemen know a small portion of people do this. They cut off the plus or dot part when your domain has a well known MX/MTA connected to it.
That still leaves custom mailservers and non-alias (as in aliases via plus or dot, not actual mailserver aliases) which does give an indication as to who is sharing your data.
