I disagree. I would absolutely run an E drain. Not manditory but i would absolutly sleep better at night.
An emergency drain is a dry drain that takes on water on the event one or borh of the siphon drains become clogged. Its basically a herbie drain set up. Its almost damn near fool proof. Id spend the time doing it now before its up and running than doing it afterwards.
Again not manditory but why not add the additional safety.
If your interested i can explain more in detail. But woukd rather not type it all out if your cool with the current set up