Firm 'No' from me.
We could bypass the issue entirely by having an option to make SP transferable; but only when the account is started.
Choose your account name and select whether/not SP should be transferable. (default 'Off' for security reasons) with no option to change it.
Existing users would need to start a new account; power down and send STEEM to the new account; but then they could buy and sell SP like they do with STEEM.
If I plan to power it up anyway, I'd rather buy SP at a discount from a guy who wants to move out quickly. Let the market decide the size of the haircut.