Pull a USB flash drive out of your Mac without first clicking to eject it, and you’ll get a stern, shameful warning: “Disk Not Ejected Properly.”
Probably not. Just wait for it to finish copying your data, give it a few seconds, then yank. To be on the cautious side, be more conservative with external hard drives, especially the old ones that actually spin.
That’s not the official procedure, nor the most conservative approach. And in a worst-case scenario, you risk corrupting a file or – even more unlikely – the entire storage device.
This is terrible advice for regular users, but I have to admit that I, too, don’t really use the safe eject features of operating systems, unless I want to eject right after completing a write operation.