Publishing the Symbian app on OTA etc. should be possible i suppose. The publisher ID need has already been eradicated(implying that Express signing doesn't require it anymore), so only if Symbian Signed website remains live (allowing users to make new accounts etc.), then people may Express sign the apps & sell them then anywhere, but as the announcement also says that Symbian Signed services will also be stopped, which obviously won't allow the thing i mentioned.