The core of the problem is described in Scenario 2, but it will be usefull start with:
I have account 1 and there are campaigns 1, 2, 3 for 3 different clients (everyone in different area, so no keyword "colisions"). I have activated Conversion tracking (Sale) for client 1 and placed the code to his page. No conversion tracking code was placed on the pages of client 2 and 3.
Everything is OK for client 1.
After a few months I can see that client 2 has 1 conversion and client 3 has 2 conversions. But there is no conversion code on their pages!
My explanation of this is here:
A user clicked on the ad of client 2 and during the months (before the cookie expired) went to the page of client 1 and bought something there. The user did not clicked on the ad of client 1, so the client 2 received "conversion" even when there is no conversion code on his page.
It makes no problem to me, the clients 2 and 3 do not want conversion data and it is only a few cases a year.
But today I looked into the tracking code and I have noticed that there is no CampaignID and also no ClientID and this leads me to the CRUCIAL QUESTION:
Is the scenario described above possible not only between campaigns in one account but between different acounts?
I am afraid, it is possible.
If I generate the code in different acounts, it is all the time the same code (no customer ID).
I have account 1 and ANYONE ELSE has account 2. We both activate Conversion tracking (e.g. Sale). A user clicked on MY ad but bought nothing. Then the user went to HIS page (not via adWords) and bought something there. User did not clicked on HIS ad, but the tracking code was shown and the user has my Adwords cookie, so I got "conversion".
Please persuade me I am wrong in scenario 2!