Even in cases where there's a short note and it's considered 'efficient', such as 'be there at 11', the proper netiquette is to then write (nt) for 'no text'. Because otherwise the recipient may not know that there's nothing more to the message, and may open the email, which wastes their time. Some email clients may show in the pop-up that there's no text, but even still if you aren't there when the pop-up pops, all you'll see is the subject and you'll open the email to see if there's anything more.
I've seen this done in online forums where people are in a conversation much of which fits in the subject lines. So there's a string of 'blahblah (nt)' which is indeed efficient but would be highly irritating w/o the (nt) there to let one know not to bother clicking.
In the case of the OP's biog lady, that's just weird.