So I went for a walk around my neighborhood ttry this out for the first time. Was super fun. I got like a 1hr 30min walk in 90 degree weather and didn't care because I was hunting pokemon. I swear to god a moltres appeared in my vicinity, I got it to two frintprints then realized it was on the adjacent street instead and it disappeared. I'm assuming legendary pokemon only give you like 30 seconds in an attempt to find it. I was also about to catch a Nidoking and my mom calls as soon as I saw him, I answer, hang up in about 10 seconds and the nido disappeared as well. Smh