Before “cloud drives” were a thing and CD-R and DVD-R were the only store media “back in the day,” one of the contracts written between my service is that once the CD-R/DVD-R leaves my premises and upon the client’s receipt, it is there sole responsibility.

If they lost it or would like replacements, it would be an additional cost.

Same, when I switched to using my FTP. As soon as the ZIP files leaves me, they take full responsibility in burning and backing them up themselves.