No the seal is not that important, the water is not under any real pressure it's just the flow you need.
Also the only difference between the seadoo connector and a normal garden hose one, is that the seadoo one has a tap in it so you can turn the water off at the connector.:rofl:
Dan you should flush every time you take the boat out, even if it is in fresh water the rubbish you pick up needs to be washed out(i.e. sand, mud, shells, jellyfish)