Khaosai,
It's similar thinking that accounts for all my Russian signatures. I was hourbuilding, and didn't want the CAA to query it, so I got my instructor to sign every line. After a bit it got to be too much hassle - and I'd defy anyone to know if the illegible scrawl in Russian was a signature or one of my cats messing with a pen! So I stopped; I had the airfield stamp, receipts for payment, photos, all sorts of stuff, if I needed proof. In the event I didn't...but I like having the signatures there anyway.
