Yeah I kind of expected that you'd have a sane `sudo` configuration… I'll have to ask the guy if he can give his `sudo` configuration for testing, but we still won't know how he came up with it. My guess is that something like `sudo -E` or modifying the `sudo` configuration to omit `/sbin` from `sudo`'s `secure_path` would trigger the issue, but I could understand you'd be reluctant to try. If I find the time maybe I can try set up a Ubuntu VM and mess with it.