Automated spam tools can be used by SEO consultants in Milton Keynes.  You can justifiably say: 'I have a YouTube video on fishing that's been seen 40,000+ times and is trusted so I call it SEO Milton Keynes and link back to my site'.  That will work to pass the trust level back to the target website or the client website.

Abuse or spamming of YouTube is so easy because the videos can not be detected or read to verify their subject content.  It's a legitimate question to ask if you should be tempted to use such methods.  The answer to this question ultimately has to be a question for the client to answer and it's not a primary question for the SEO consultant.  Guns don't kill people, people using guns kill people and the same is true of black hat.  The deceitful  labeling of a popular YouTube video is simply black hat.  It's cheating and you can equate this activity to putting a packaging wrapper around the video and calling it something it's not.

If the SEO consultant wants to use such black-hat methods then they should not, in my view, use black hat on behalf of their clients.  If you expose your clients to being deluded into thinking that you have more power and influence over Google results then more fool you - the so called consultant. Some people would call this sales - I don't it has crossed the line and leads to trouble.  It's not professional and in fact I would consider it careless and lacking in a duty of care to the clients' best interest.  Taking short cuts, with associated high risk, is often the sign of a desperate and foolish decision.