As far as I know, the memory check can't be turned off in the Memory Control Panel on a Quadra. I seem to recall that it requires a PPC and MacOS8 — possibly 8.5 or 8.6. It requires pressing Command and Option simultaneously while opening the Memory Control Panel. It's well hidden, anyway.

I can only assume that the feature was introduced when memory complements began to go way up, and then only for the select few who could afford a lot of RAM. It wasn't really needed when 64MB in a PPC was a lot of RAM.