I've got the Exceptions.plist on my 10.6 system, and it's got 48 entries in the MinimumVersionRequirements section. Mostly Apple stuff, but also Parallels Desktop (and I've triggered the error message with this), Intego Virus Barrier and NetUpdate, Elgato EyeTV, and a few others that are a bit surprising: SPSS 17.0, Macromedia Director MX 2004, and Asobo's video game tie-in to Ratatouille.