Would you trust one automatic box for a few days away?

Going away for a few days make me less worried about scooping and more woried about what happens if the box stops, fills faster than expecte or the cat simply refuses to use it. An automattic box can reduce the daily chore but someone still needs to check the cat, food, water, and litter area while Im gone. Id also be tempted to leave a regular box available instead of making one machine the only option. people who travel with an automatic setup do you still leave out a backup box when someone is checking in?