And any person deciding to announce 1.2.3.0/24 to the open network, would have to face a massive traffic storm anyway.  prop-109 by Geoff Huston mentions the traffic flowing to certain easily-remembered ranges.  Assuming that 1.2.3.0/24 gets even 50Mbps of traffic if I announce it to the Internet, that is till still an expensive pipe, and probably not worth it on the off-chance that a random user will use it and allow "evil me" to redirect him to the particular bank that he is a member of, and which I am forging a website for.

Never underestimate the willingness of a malefactor to subject hosts he controls (but probably doesn't own) or even hosts he doesn't necessarily control to vast quantities of traffic.