It's generally the theme that whenever someone has a tank minder, something always goes wrong...
I recently went to Wales for the week, and as I don't really have any family nearby, and wouldn't want people in my house anyway, I filled up my 25L top up container before i went, fed the fish very heavily the morning before I left, and stocked the algae clip up to bursting with a good few sheets.
When I got back, everything was still running perfectly, all fish accounted for and none looking thin or anything (as even when food ran out, they've food in the tank to eat anyway, algae, copepods, etc.
It's a big risk doing what I did, but I was confident my set up could handle it. I certainly wouldn't like to do that on a regular basis though.