There are 3 distinct roles the person that profits from the advertising (owner of service), the person that manages the campaign (sig operator) and the person that holds funds should one of the other two disappear (escrow).
If a single person does more than one role, there is a possible conflict of interest.
I would personally say as long as the person paying out the funds is not the same as the person who is receiving the advertising (the entity that is incurring the debt as a result of holding the signature campaign) then it should be considered as escrowed. The reason for this is that if a company were to have their services advertised, have an escrow both handle payments and escrow funds then if the escrow were to run away then the company receiving the advertising would still owe participants their payment. As long as participants do not edit their enrollment post then the owner of the service being advertised should have enough information to pay participants.
IMO the bit-x campaign is 100%
not escrowed because funds are sent to bit-x addresses who then process payments therefore bit-x are effectively handling payments to participants. Marco holding funds on their behalf is nothing more then a device to install confidence that should not be there.
On the other hand the ocupy campaign is escrowed because if the owners of ocupy were to run away then they would still be 'protected' by marco (if you trust him enough, but that is another discussion) if the owners of ocupy were to run away, and if marco were to run away with his escrowed funds then the owners of ocupy would still owe the participants of the campaign.