"Any offense you commit now as a minor will stay on your permanent record forever. There is no sealing of records any more. The government changed the law a few years ago and now you are screwed for life. While assault 4 is only a misdemeanor, it is still considered a violent offense and will keep them from many things in life they may want to do in the future.

There are no breaks anymore once you involve the law..."

Actually, there are a bunch of ways to allow the kids to take responsibility for their actions, face some sort of punishment/rehab (community service, gun classes, jail - although jail would be unlikely for this case with a kid without significant criminal history in king county) and still not be affected down the road if they comply with what they are supposed to do.

Juvenile courts allow for "diversions" of juvenile misdemeanors. This requires a juvenile go to a community diversion committee, do some sort of punishment/rehab (probably a gun safety  class and community service) and the case is never filed, therefore there is no conviction. RCW 13.04.080

Even if a child fails to comply with diversion or is never sent to the diversion committee because the prosecutor deems the child's history to be to significant or the crime to be to serious, the prosecutor may negotiate to a different charge, one that carries less stigma than assault. (I have no idea if there's a statute, but I'm a prosecutor and I do it all the time).

Even if a child pleads guilty to Assault 4 (or another charge), the prosecutor has the ability to recommend a deferred sentence, which results in the case being dismissed if the child satisfies the conditions of sentence. First time offenders commonly get deferred recommendations. As your criminal history piles up, you are less likely to get that consideration. (RCW 3.66.067.)

Even if the prosecutor elects not to recommend the deferred sentence, the court can impose it over the objection of the prosecutor (same statute as above, same discretionary considerations). 

Even if a deferred sentence is not imposed and there is no possibility for a later dismissal of the charges, the child may ask the court to seal the conviction record by WSP (When you do a criminal history check, WSP provides the response, therefore an employer requesting such records would not be made aware of it). State v. Noel, 101 Wn.App. 623, 5 P.3d 747, (2000).

Even if you were convicted of a felony (not the case here), a juvenile or adult may seek vacation of the records under RCWA 9.94A.640. Vacation of the record also prevent WSP from reporting the conviction. The assertion that Assault 4 is considered a "violent offense" is 1/2 true. Yes most people consider it violent b/c you assaulted someone, but for this purpose and pretty much all others in the criminal justice system, a violent offense is defined, is limited to felonies and Assault 4 doesn't qualify. RCWA 9.94A.030

It is true that none of these possibilities provides for sealing of the court file itself, but the court file is not what is searched when one asks the State of Washington for a crim history check, its the WSP file (There is no easy way to check all of the court files in this state, they are kept individually by county). Sealing of a court file has constitutional considerations and requires "compelling circumstances" which are unlikely to be found in this case, even assuming the kids stays on the straight and narrow for an extended period of time. Anyone who actually went to the trouble of doing a county by county search and found the file, however, would also see the nature of the offense, the resolution and whether the child complied with the requirements of any sentence. I suppose someone could decide to not hire someone for a job b/c of something like this, but it would be an odd decision if this was the only black mark on the person.