I guess it will depend on whether the ADs and president believe Harbaugh truly was blindsided by the revelations. If so, they know it could happen to them just as easily, any investigator worth their salt should be able to come up with some dirt on any of the other 13 schools. If on the other hand they have evidence Harbaugh, or at least senior assistant coaches, knew about it and there is only implausible deniability, then they might be comfortable that their own programs are clean enough to avoid getting caught in a chaotic loop of investigations and counter-investigations.