I see it on a regular basis from genealogists at all levels.
"I'll help you trace all your great-grandparents. I have success in 97% of cases. I'll find your ancestors." Others make similar statements.
It is not just the inexperienced who make such claims on their websites. I see it in promotional materials written by those with various certifications and years of experience. It always leaves me a little frustrated and wondering how many potential clients believe that success in genealogical research can be guaranteed. It cannot.
Readers of this blog and my newsletter Casefile Clues know that occasionally I hire genealogists to work on various problems for me. Time and distance does not always allow me to research everywhere I want or need to. Usually I hire genealogists I have dealt with before, whose work I have seen elsewhere, or who have been recommended by someone I know. If I am considering hiring someone and their website or promotional material indicates any suggestion of even a hint of guaranteeing results, I go elsewhere. It is just a personal preference of mine. I want someone who knows their "stuff" and knows better than to even hint at guaranteeing anything.
I'm working on more in a series of hiring a professional researcher for Casefile Clues. The researcher I've hired and I have agreed on what will be researched, what copies will be made (if information is found) and how much time will be expended. Nowhere did she promise me any results.
I'm hoping she finds what we are looking for. She is too. But we both know that there are no guarantees in genealogy research. You should too.