The information behind a link can be changed at any time or the link can be "broken" at any time. This doesn't generally happen in well run companies, but if there was a legal dispute between owner and an agent, it would be possible for the agent side to break or alter the information behind any link.

In order to give owners more confidence that ownership statements cannot be altered I far prefer a statement to be sent as a PDF. That way the facts are frozen in time and if there was any dispute between agent and owner the owner would have a series of PDF's to present in court.

Also without any legal dispute you are also asking the owners to take an additional step to print out the link so that the information is frozen