Problem, aimjoy, is that deposits are often very much less than 10%.
I know of someone who had a property worth about $10m, from memory. He got a DA that increased its value significantly. Then he signed a contract to sell for $30M, held by a $50K deposit. The contract went unconditional, on the proviso that the vendor had to withdraw his DA because the purchaser wanted to do something different (perhaps units instead of townhouses or vice-versa, something like that), allowing the purchaser to lodge a new DA.
After months of mucking around, the vendor decided not to proceed (couldn't get the approval they wanted or something) and decided to pull out and throw their $50K deposit away. Apparently they were structured very well so there was no way to get anything more from suing them.
So this guy has a property whose value he had increased from $10M to $30M, that's now worth only $10M-ish again because now there's no DA. And he's got the $50K deposit but it's cost him perhaps $300K in holding costs waiting for the deal to finalise.
Adding insult to injury, a couple of months after the deal fell over, he got a bill for $750K commission from the RE agent... He ultimately paid it and considered it a lesson learned.
Moral(s) of the story: 1) When you're selling, make sure you have a big enough deposit to cover the deal falling over after it's gone unconditional, and 2) Change the clause such that the agent only gets their commission if the deal settles, not if it goes to unconditional contract.