The initiative process itself "weeds out" frivolous proposals.  First, it requires sufficient signatures on the initiative petition to quality for the ballot.  This is not an easy task.  We have seen both initiative and recall efforts "weeded out" when they've failed to achieve the required number of signatures.  Secondly, the election itself is a further "test" of the initiative.  Supporters of an initiative, once they've successfully gotten it on the ballot, must then gather the support of a majority of the voters to have the initiative adopted.  

Those special interests supporting this initiative veto measure do so because they fear the initiatives referenced  a) are, in fact, constitutional and b) just might get on the ballot and c) just might be adopted.  BTW: The initiative process has been part of the US Constitution and the Oregon Constitution for over a hundred years.  It is certainly a "legitimate process" and a key part of American democracy.   regards, Gary Crum