Realistically these things aren't going to be operated in-flight anywhere close to the proximity of other craft. They'll motor from dock out to a predefined and clear[able] "runway". Once you're clear of a port most stretches of open water are mostly empty (even those within sight of shore) -- it should definitely be possible to plot "cruising-altitude" courses that never place you within (N) of a hazard. And if there is ever any uncertainty or doubt about incoming situations you can always drop down to a safer mode to chart a new course.
No. All of the major ferry routes they are proposing to serve already have a significant amount of vessel traffic. Seaglider operators will have to obey the rules of the road to avoid collisions just like any other boat.
Anywhere near significant boat traffic (e.g. in harbors), we'll be on our hydrofoils at speeds of 20-50 mph. So in these environments, we're just another boat (albeit a very comfortable, wave tolerant one)
We dont leave the foil to takeoff onto our wings until we leave the harbor. This doesnt need to happen on "runways" though. We'll already be at takeoff speed (~50mph) as we're leaving the harbor, so we really just jump out of the water whenever we choose to. This way we dont need to clear long stretches of water for a "runway", which has limited seaplane operations.
Absolutely agree: Seaglider operators will have to obey the rules of the road to avoid collisions just like any other boat. WIGs are actually already in the COLREGS (we're last in line for right of way, but on the list!), and our sensor systems will ensure that seaglider captains have excellent situational awareness.