CoolP:

Your points, of course, are well-taken... ;D...

In my experience, even though I press the attendant button (of the most sophisticated voice-activated multi-crew experience expansion packs available these days), no dinner materializes from the galley (although voice-confirmed promises are made).

In fact, your 3rd possibility overrides... ;)...

More seriously, I did look for a PTD utility once when I forgot to pause my (LNAV+VNAV) active long-haul flight (on my arm-chair, mind you). When I returned a couple of hours later, the (gear-less) aircraft was found stuck to the ground in the vicinity of the DEST airport. I can only imagine the last few minutes(?) of the flight while the plane gallantly must have tried to follow the FMC instructions to reach its intended STAR and ILS RWY!

BTW, some like-minded virtual flyer had created an utility (aptly called "iwillbeback.zip") on avsim:

http://library.avsim.net/esearch.php?DLID=24428&Name=&FileName=&Author=&CatID=root

However, this being dated back to 2002 (and for FS2002), I've not tried it....