Good day/evening/night to all!

I need help and may be there's some kind person who would give me some clue/advice, I hope.
Yesterday I noticed a strange thing on my NT box (NT standalone Server 4.00.1381 Service Pack 6). I created a text file and set its permission to Everyone/NoAccess. Everything (copy/move/delete operations denied) was allright until I pressed Shift+Del combination just to test permission work. Was I amused, gentelmen? I say YES! File was successfully vaporated into nothingness!
I tested this thing on dosen another stations/servers and everything was the same everywhere!
Can anyone explain such strange behavior of NT?
P.S. At home I got NT box (same as described above) but I got NTFS 5 there instead of NTFS shipped with NT Server 4.0 and things are as they should be - if Everyone has NoAccess or only Read permission set for some files/folders then no one can delete them. So I ask - is this NTFS 4 bug (or feature :)) or I misunderstood something? And is there any way to fix this nasty feature (or rather bug :)) besides installing NTFS 5?
Thanx for your replies in advance!
Bye!