In this case, Fabian's CV (linked from his GitHub profile, linked from his HN profile) does claim MySQL experience - correctly capitalized.
But yes, I also get suspicious when people can't spell a technology correctly. For example, anyone who has spent time reading some documentation will know that Lua is capitalized in title case, and not written LUA.
Really? I will claim you will not meet many engineers who know more about Tcl than I do, and I can't remember whether it's TCL or Tcl. The absence of that knowledge has not impeded me from editing the Tcl interpreter itself.
I am not convinced such pedantic measure of spelling is an accurate predictor of knowledge, to me it sounds more like elitism.
Or, table stakes to distinguish folks worth spending time on & folks not worth spending time on. Since it's so easy to get the little things right, anyone who doesn't is just a bit suspect.
It's like discarding resumés which arrive with large food stains on them. It's just too easy to print off a clean copy, that anyone who doesn't must be a bit off.
Using insignificant details as hints is probably a valid strategy, especially when you have to make quick decisions with limited information. But they are not primary indicators and are hardly worth their own comment. This entire thread is off topic and of dubious value.
In Lua's case I agree that spelling is a predictor, but only because if you ever type LUA somewhere in the internet there is a 100% chance of someone showing up to correct you :) Its actually a bit funny.
But yes, I also get suspicious when people can't spell a technology correctly. For example, anyone who has spent time reading some documentation will know that Lua is capitalized in title case, and not written LUA.