Quick question - you wrote "There are few safety checks" - did you mean "There are a few safety checks"? I'm trying to figure out if this is implemented badly or not.

The basic design outlined in "important notice" section on brochure page[1] sounds a bit simplistic to be honest - it doesn't seem to have a PIN or really advanced checks, more towards "we've done our homework" checks, but OTOH, they did seem to have done homeworks.

1: https://lp.da.pf.japanpost.jp/