Strangers collecting ballots have been reported in different areas of King County and Seattle. Representatives from the Washington Secretary of State’s office and King County Elections say collecting ballots is not illegal. However, neither office recommends giving a ballot to a stranger.
I recommend not giving your ballots to anyone. Put your ballots in the US mail by Tues Nov 6th or in King County Elections drop boxes.
Track you ballots online. The Ballot Tracker will show if the King County Elections has received your ballot and where it is in the process of being counted: http://info.kingcounty.gov/elections/ballottracker.aspx
King 5 carried a story about the collectors: http://www.king5.com/news/politics/Elections-officials-caution-voters-on-canvassers-offering-to-help-with-ballots-17704