I'm still waiting for my engine to be re-installed on my plane so, in the meantime, I rented a 172 this past Saturday to keep my hand in and make sure I didn't get too rusty. Because it had been long enough since I'd rented a plane from Snohomish Flying Service, I had to take an instructor with me. While the FAA has no problem with me hopping in a 172 and taking it up, SFS has their own currency requirements driven, I suspect, mostly by insurance requirements. Other than the added cost, though, I didn't mind as it gave me someone to talk to and share stories with as we were flying around. While we were up there, something pretty cool happened. After we took off we headed southeast toward Snoqualmie Falls at about 3000 feet. We flew past the falls then turned around and headed back. This plane, N734LQ, is equipped with a Garmin GTN 650 GPS navigator with ADS-B In, so it can display nearby traffic. Ross, the instructor, noticed an interesting-looking plane heading in our