As previously mentioned, if he's willing to falsify logbooks what else would he falsify - mx maybe? I've had this happen with several students in their own aircraft. Illegal mx that went well beyond preventative. And stuff that was obviously done but was never logged because they did not have an A&P. I also caught a student out flying the aircraft solo without an endorsement because it was "his airplane and he'll do what he wants with it."
I am very careful with students in their own aircraft and require that I look over the logs before I start flying with them and conduct a BFR/IPC. "Pitot-static check? Who needs that? I can save that money by just not doing it....."
