... and something that appears to be a professional camera case
doesn't?

Indeed it does. My suggestion was to use a battered small rucksack. It has
served me well for this purpose on many occasions.

I wouldn't assume, though, that the OP (or anyone else) is planning to
take a laptop into crime-ridden areas, or be dumb enough to leave it
unattended ...

In real life, this is sometimes just unavoidable.

Christian.