Congress had all good intent when they introduced the idea of rolling a decedent's unused federal estate tax exemption over to his or her surviving spouse (so-called "portability"). Use of portability is - not surprisingly - more involved than first meets the eye. However, it should for all estates be elected, since one never knows when it may be needed. While I would not ignore pro-active estate tax planning and rely on portability as a planning technique, I strongly recommend that executors elect portability as a prudent and appropriate protection. Granted, election requires that a federal estate tax return be filed timely and the election made; but prudence dictates that this take place.
In fact, an executor nay feel obligated to make the election for his/her own protection, so one is well advised in his/her Will to direct the executor not to make the election is that is the intent.
To the contrary, it may be advisable to consider directing the executor to elect portability if there is any concern that the named executor may decide not to make the election, either thru oversight or for more nefarious reasons.