You're all missing something very important when worrying about the prices. I assume you could add stats and maybe even prove me wrong but here goes:
SRL is tiny. We have 300 members sign on a day, most of which are registered users. Say of the 300 members a day, a quick eyeball says they're about 1/3 Jr. or higher. That's 100 people a day who can see the Jr. Member section.
How many of those people have the requirements to profitably farm red spiders' eggs (ie not Wildy). How many of those people want to? Even assuming 100 people a day are using your script, lets do some quick math. They're 400k/hr meaning roughly 400 eggs per hour are collected. 100 people a day means roughly 40k eggs are collected per hour. Cosmas has said his script works about 6 hours a day so as not to be instant-banned, so we're looking at 240k eggs per day collected. Even with 4 accounts farming for this long, you're looking at 1M eggs per day collected. (This means 400 accounts are now farming this method)
400 accounts farming your script is 1M eggs per day. It's pretty safe to say that this would be double (possibly triple) the amount traded in an average day. This is based on the fact that the 100 most traded item is average ~10M per week trades, and the price point of eggs gives you the impression that they're probably in about the same supply/demand bracket, I'd guess about 300-500k per day.
Markets are tough, but assume that 2x supply means 1/2 the price. You're looking at about 500gp each for an egg, giving you about 200k profit per hour instead of 400k per hour. How many people will still farm them at that price? I assume not as many, because there are way better methods than that. Then what happens? You decrease supply by 2, maybe 3 times as a huge amount of farmers move away from the method? Or do people just farm it anyway for as much money as chopping logs? I'd bet that supply bottoms out and the price increases again.
That's the whole point of supply/demand that gold-farmers don't seem to get. Using extremely high foolish estimates for script usage, I still don't imagine you'll kill the market. If you did bring the price down to 500gp each I'd be there investing all my money in red spiders' eggs and waiting for the botters to drop like flies and the price to go back up to 1k each. When supply is high, people flood the market at -5% to sell their items, but when supply is low, buyers have to offer +5% in order to be the best offer in the GE. The whole system is set up to work that way, a tiny community of 300 people isn't going to crash anything.
Proof of wizard guesses (TLDR: I guessed body runes would top out quickly and get stuck around 60-70gp. They promptly crashed back to 60gp and have been hovering a little under 60gp for the last 4 months.)