I am curious. If what you described is a standard technique people can use, what prevents the recruiters/talent acquisition to, by default, discard resumes/CVs without exact dates?
I assure you it is a standard practice, but why would recruiters discard resumes without exact dates 'by default'? Because the assumption is that those people are 'old'?
That may answer the question for you, but ageism is a legal concern and disqualifying candidates because they didn't tell you when they graduated isn't dissimilar to asking someone how old they are in a job interview and refusing to hire them if they don't.
As someone who hires, I like to see dates because I want someone that has a track history of sticking around for a while. I don’t want to waste effort on someone that has a history of changing jobs every year or two. Dates help show that.
When I started my career as a programmer it was a bad sign if people didn't stay 5 years at least at a company. But these days hardly anybody stays longer than 2 years unless they're being paid exceptionally well. So it's no longer a terrible sign if someone doesn't last more than 2 years. It can actually be a bad sign if you work at a big company for 10 years because you're probably out of date because you focused only on their tech stack .
That may answer the question for you, but ageism is a legal concern and disqualifying candidates because they didn't tell you when they graduated isn't dissimilar to asking someone how old they are in a job interview and refusing to hire them if they don't.