I think that is a symptom of a larger problem to be honest. Odd screws don't stop tampering, they just cost you lots of money to tamper. Why bother? this is another circumvention industry that doesn't really need to exist.

My Lenovo can be stripped bare and reassembled with a Swiss army knife in a few minutes and not much effort or head scratching.

For reference, Lenovo have a web site which SHOWS you how to take your stuff to bits:

http://service.lenovo.partner-management.com/et.cfm?eid=1369

Pick a unit, click the Take course link. Videos for everything.