The tie wrap is pretty well accepted except in areas where something more drastic is required by locals or even lake wide such as handle removal and hose removal.
But a few years back some boat builders decided less sea cocks were better and the discharge port was above the waterline with no sea cock to secure and just a button on the electrical panel to discharge. Some cruisers decided to take it one step further by putting a key switch in and placing the key in a secure spot.
After years of boarding teams getting into arguments over all this...the office of the USCG Commandant (may have been a subordinate office with proper authority) came out and described acceptable methods beyond what the CFRs state.
If I find anything today or soon...I'll make sure I share it.
I remember that too from my Auxiliary days. ...ty-wrap, padlock on the seacock, keylock switch, 2 switches in series, locked head compartment... There were multiple acceptable ways to comply. The whole point was to require at least 2 actions to prevent accidental discharge.
I'll have to find the CFR bases but here is the CGAuxiliary VSC Manual (
http://www.uscg.mil/directives/cim/16000-16999/CIM_16796_8.pdfwording )page 26 as it exists today:
No-Discharge Areas.
Vessels shall not discharge sewage overboard in an area designated as no discharge. A Type I or II flow-through MSD must be adequately secured while the vessel is in a no-discharge area to prevent any overboard discharge of treated or untreated sewage, such as:
Closing the seacock and padlocking, using a non-releasable wire-tie, or removing the seacock handle,
Locking the door to the head with the owner/operator in possession of the key in not-discharge controlled areas.
A combination of switches that have to be pressed simultaneously or
Switches that can only be turned on after inserting a key.