We aren't going to iNotes because we are a 50/50 Mac/PC shop and iNotes doesn't work on the Mac. I did find one Technote on the issue, but unfortunately this is not a user I can quiz that thoroughly.
You are correct that the problem reported in this Technote would require some careful quizzing of the user or looking over her shoulder as she works. And most likely a user who makes this mistake won't quite remember it later on.
You should point out to the executive (although she won't want to hear this) that current Internet e-mail is not a reliable mechanism. No message is guaranteed to be delivered. Anyone who absolutely counts on Internet mail as a reliable delivery method is making a mistake.
Having said that, e-mail works pretty well. If she is getting fairly regular "dropped" mails, something is indeed wrong. It is just hard to say what it is without watching the user work. Best of luck.
This was first published in May 2003