In episode 290 of Semantic Mastery's weekly Hump Day Hangouts, one viewer asked if SERP watching can hurt a website's ranking.
The exact question was:
Hey guys, does SERP watching hurt a ranking for a specific website? My car dealer client is rising rapidly for a major keyword, almost too fast (shoutout to SM). I showed him the progress and he got so excited he's checking it every day. I requested he take it easy, but if he's actually hurting things, I'll tell him to stop.