I am.
Will play a test game tomorrow on std/std/settler. Will play normally until research labs. Then save, and see what turn I launch spaceship with normal play, and what turn I finish by exploiting this. I'd expect the exploit to be at least 15-20 turns faster, maybe more.
Did this today. Std/std/settler/inland sea, just played a random, not that great start. Never had access to coal, no CS had expanded their borders to actually include their coal, so didn't build any factories.
t162 I had 4 research labs.
t170 I saved, popped I think 9 scientists without getting any techs. That put me at 52,595 of 43 to research sailing. Got sailing, optics, compass while building the overflow, and I was at 150,454 of 927 for Astronomy, which nobody had.
Kept getting 1 tech per turn, on t199 I had all spaceship techs, 20k overflow left over, and 4 more unpopped scientists (2 from hubble, 2 naturally spawned), good for another 25k beakers. Popped them, t201 I ran out of overflow, I had everything except stealth & future tech, I was 3 turns from stealth.
t204 I researched stealth and launched my spaceship. Bottleneck was production/gold. Popping 1 or 2 extra scientists earlier, to get research labs even earlier, and it would have comfortably been under t200.
Then reloaded t170, popped the scientists normally, heading straight for rocketry. So apollo program was completed at least 10 turns earlier. But this time, the bottleneck was beakers. I didn't get the final spaceship tech until t220, so launched spaceship on t221. That could also have been a couple of turns earlier. Wasted some time starting on ISS, and I let arts funding get passed on the same vote as ISS, so the final scientist that put me over the line came ~2 turns later.
But end result, on settler, without timing it at all well, this exploit saved me 17 turns, nearly 10% faster.
It's not as ridiculous a benefit as available on deity, but it's still significant.