Hmm I disagree.
I own several domains and use sacrificial addresses for small or new suppliers and unique addresses for long term suppliers.
These addresses are forwarded onto my actual email addresses.

So maybe I would use my.sws.bk@mydomain.co.uk for my Swiss Bank Ltd account (yeah I really have one - Not).
This junk is targeted specifically at the my.avast.acc@mydomain.co.uk (not the address I actually use) but you get the picture.

Its not a lucky guess or randomly generated.
Anyone getting this ?