We have 1777564 contacts where the field do_not_trade is set to 1. This is being set when we insert a new contact by this line

'do_not_trade' => $msg['anonymous'], // FIXME: has the wrong meaning

Careful reading of the code line will suggest I am not the only person to question us setting this :-)

From discussions I've had so far I believe this is not used. It causes contacts to be seen as a merge conflict so we should either come up with a rule e.g if one of them is do_not_trade = 1 then set the merged contact to have that value OR simply stop setting this field & wipe the data out of it.

So far my discussions have suggested the latter is a good idea but I think I need @awight @K4-713 @Ejegg & @CaitVirtue to confirm before I do this