Nah, It will cost you a capital ship and some negative income.

With the negative income you will undergo while abandoning the planet (which will cost you more than you saved on extractors), as well as the lack of being able to use your Akkan during that time, this is no exploit at all.

Dropping a planet takes about 60 seconds (iirc, not something I do every day), and with underdevelopment at about 2.5 credits per second this will run you about 150 credits.  So yeah, in theory you're making a savings.  However, your colony cap's time is worth more than a few free extractors, it's much better to just get moving.

Yes, when I tried it before creating this thread, it was with level 2 colonize, which gave me 2 free resource extractors.  I then scuttled while at the same time fighting heavy militia (something I had to do anyway, so time with my capship wasn't being wasted), and recolonized to get the third extractor just as I was finishing up with the militia.  (It would be better with the 4 extractor planets as you said.)

It might also be of benefit to do on some heavily defended planet which has 3 siege frigs.  Will 3 siege frigs take out the colony before scuttle can?  If so, you are in the negative for less time, cashwise.

At any rate, thanks for the comments, and I'm glad to hear this isn't an exploit.

I think we have established that it isn't an exploit.

how about fixing the colony ability of the vas eggy? Totally sucks.  Maybe it should be 60 secs but 100% increase build rate and then 200% then 300%

It's really only worth attempting on your 1st 2-3 planets.  After that you're talking resources equal to maybe 2 light frigates that you'll be getting within a few seconds anyway.  (Assuming you fully research infrastructure on those planets for max creds.  Why wouldn't you?)