Has anyone any experience of post-dating either notices or weblogs entries?

Reading the documentation (and asking the VoiceBot) it appears that post-dating articles is possible if you use the prescribed date & time format (i.e. for whatever reason you don't want the article to appear immediately).  I tried it recently only to find out that the article appeared immediately (along with the associated email notification) rather than, as anticipated, 4-5 days after it was written.  Doing it this way I assumed that I wouldn't have to remember to publish it (so one item less on my to-do list).

Any advice welcome, or of course it might be a simple gremlin that has crept into the system.

Alan