However that experience counts for things you don't get elsewhere. Ie, I may not know a particular language but I can learn it fast without complaining that I was never taught that in school. I also understand lots of practical things, how to write a device driver that doesn't exactly fit the template of the previous job, how to spot bugs in code quickly, how to question the specifications if they don't look right, and so forth.
So it depends on what you mean by "relevance of experience in technical fields". If you mean knowing all the particulars of the latest Java incarnation, then you're going to have bad results for both younger and older workers. But if you mean "knows how to get stuff done" then the older worker will usually be the one who knows it after a brief time spent getting up to speed with a new environment.
Now if knowing modifier keys is essential to the job, then spend 5 minutes explaining it and move on. It's irrelevant to the big picture and it says nothing about decayed technical skills. Everyone starting a new job has to learn new stuff, no one ever comes pre-loaded with all the stuff they need to know unless it's a really stupid job.