I think you have a valid point, particularly where mail is delivered to apartments where there is only one letterbox in the front door and all mail is left on a table in the hall for individual to pick up, and is also on view to anyone passing by. I had my passport stolen by a bank employee for certain, but I was unable to prove it, it was nearly new, and I had to replace it again, a very costly business
I would encourage you to write to H.M.P.O. and maybe even your M.P. and point this out.