English Law/Patents Law: Patents, Trademarks, Copyright

In the sentence:
The winners may be asked to consent to filming a television appearance in relation to the prize (“Contribution”) and in such event the winner shall consent to the recording and/or broadcasting of the Contribution and the winner’s parent or legal guardian on behalf of the winner shall assign to [company name] all rights of whatsoever nature including all copyright in respect of the Contribution and grant all further consents or licences necessary to enable the fullest use of the Contribution throughout the universe in perpetuity by any and all means in any and all media, whether now known or hereafter developed, without liability or acknowledgement.

"liability and acknowledgement seems to be a standard expression". Could you clarify, what "acknowledgement" means in this context? Thank you in advance for an answer.