One of the computers which I bought several months ago is occasionally making a fuzz about an alleged fan failure on a header to which a fan is connected, but where I did not connect the RPM sensor pin (because Supermicro's BIOS has a rather high threshold to detect fan failure). This made me go look at the system health logs of those computers of mine which have a BMC ... and discovered one ECC error logged on January 6 on one of these computers (a correctable error).
That is: Anecdotal evidence suggests that bit errors in RAM happen. If your computer does not have the hardware to check for (and if possible, correct) these errors — or if your computer has it, but you never look at the log — this does not mean that you do not have these errors. It only means that you do not know about these errors.
PS, I'll stop now since this is mostly off-topic in this thread. Just one more remark: Today's computers have hardware check sums (or better) everywhere — internal to the CPU, on the PCIe buses, in storage controllers, on the cables to storage devices, in storage devices including their storage media, on networks. Prominently absent: Check sums in RAM at the "client" computing tier. But RAM is subject to the same trends as CPUs and mass storage and networking: Higher density, higher speeds, lower power.