The phrase "incidental contact" refers to unexpected or unintentional physical contact with someone or something while engaging in another activity. Full definition
No more 50 - yard penalties for incidental contact. (sbnation.com)
Officials like it when you get that head around and are tracking the ball --- that makes incidental contact secondary. (sbnation.com)
Humans can easily develop tularemia through incidental contact with infected rabbits, cats, rodents or other animals (and the ticks or fleas that may be on them). (sciencedaily.com)