Yes. The same devices can be scanned into multiple accounts within Cisco Active Advisor. Only devices scanned in using a particular cisco.com user ID will be visible to that user within the portal.
The Cisco.com ID used to upload the scan also determines access to Cisco service contract information available within the portal. Only cisco.com IDs that are associated with contracts can see the details of those contracts within the portal.
For example, if you have associated two cisco.com IDs to a particular device's service contract, and then scan the device into Active Advisor under three cisco.com IDs, two of which being associated to the service contract on the device and one not being associated, on the two accounts you will see full contract details and on the third account only an indication of the presence or lack of a contract covering the device.
You can look up whether a device is covered under a service contract generally via it's serial number using this link:
Cisco support contract information is only viewable for users whose Cisco.com account is entitled on the support contract for the scanned device.
For more details on support contracts and warranty information within Cisco Active Advisor, please see:
Included in the article above is a link to the Cisco Commerce Software Subscriptions and Services (CCW-R) tools, which will allow you to see what Service Contracts are currently associated with your Cisco.com user ID.
If you aren't already associated with a contact, you will need someone already listed on the contract to open a Cisco TAC case in order to add your Cisco.com user ID to also be associated with the same contract.