Isn't email tracking usually done using an image beacon and aren't images turned off by default in GMail? It sounds to me like he may have accidentally purged a lot of active readers by putting too much faith in flawed reporting tools.
Sure, you should never send email to anyone who marked you as spam, but deleting people just because they don't have images turned on is probably overkill.
Sure, you should never send email to anyone who marked you as spam, but deleting people just because they don't have images turned on is probably overkill.