[drusepth]

Just alt-tabbed in from writing runescape bots to HN and wanted to say that's still the case (for the client I use). The code is pretty complicated now but still functions much like you say. Mouse position is tracked, then any input which repositions the mouse accelerates at a "reasonable rate" and with a randomized curvature to get "close enough" before it self-corrects and gets a pixel-perfect click.

A few years ago the client stopped sending mouse data back to Jagex altogether. Luckily, I don't think there's many poor developers tasked with trying to recover any signal out of that anymore. :)