They could be.That is not entirely correct.i am hearing that two from Oregon may vote for TrumpHe'll get 306.
According to the supreme court they don't have that option. Electors are acting as agents of the States via the winning party in that State, it is not a discretionary position.
FindLaw's United States Supreme Court case and opinions.
Faithless elector - Wikipedia
According to the Blair case a state can hole electors accountable and/or replace them should they fail to pledge for a specific candidate. Not all states have laws that bind electors. In this case, Oregon does have a faithless elector law:
ORS 248.355 - Selection of presidential electors - 2015 Oregon Revised Statutes
That law, however, does not seem to have any enforcement options to it. If the electors pledge to Trump and then vote otherwise I do not see any repercussions to that action.
They could be subject to any State maleficence or betrayal of public trust laws. Electors voluntarily agree to the party rules to support the nominee of the party when they enter their names to become electors and if their party wins, they are bound by those rules. They would have no defense for not following the rules.
Again, I do not see the statute that would apply to them. I am not saying that it is or is not there - just that I do not see any actual legal connection with the law I cited and what happens when an elector breaks that pledge.
There are many laws dealing with misdeeds of elected public officials that aren't tied to specific positions.