If passed, would depend on the language.
If written to just ban future sales, no.
If written to ban all ownership and no provision for those already legally purchased and possesed, then yes, if found with one not meeting the requirements, could be charged, taken, whatever, again, depending on how it is worded.
And sadly, this is not going to go away. Sooner, probably than later, they will tire of spinning their wheels and it will be written up and put on the ballot for public vote, just like baiting & hounds was for bear... We all know how that will turn out!!
Are you saying "yes" to a ban that affects everyone and criminalizes those already owned by people? You think that's okay?
Absolutly not!
Please reread the entire text of my post, not just the piece you highlighted!!
Was attempting to answer a question posted prior (bolded and underlined in the following qouted reply to the same question I was answering):
From the article: Sen. David Frockt, D-Seattle, said a number of states have passed similar legislation. He said Washington’s proposal would grandfather in legally owned assault weapons.
So, does that mean that if you already own an AR, then if this ban passes you can still go out shooting your AR? Wouldn't talk of this make sales skyrocket? Wouldn't this be a great time to go by an AR or two to get ahead of the ban?
Say you already have a firearm with a high cap magazine and they ban the mags. Are they simply banning the sale or do you then need to plug the magazine so that you are limited to 10 rounds? 
Yes. Yes. Yes (before prices skyrocket because we're all doing the same). None of the news reporting sites have specified on the mags yet being grandfathered or not but my guess is NO.... I gave all mine away that were over 10 round ct 
Calm down and please refer any future questions via PM if you do not understand something that I have written, no reason to clog the thread needlessly.
I will be happy to try and explain anything you do not understand.
