I have other 3 other admins on each of my sites, all of whom are people I know in real life and see on a regular basis.
On the off chance that someone got into my sites like that, I still don't worry about it, since everything is backed up to tape drives on a nightly cycle. The worst thing that could ever happen is a loss of 23 hours worth of data, if a hack occured right before the nightly backup.