The meatspace risks of online gaming are minimal. It is so rare as to be newsworthy when an online gaming confrontation leads to physical violence. The few incidents I recall were all in east Asia, so I estimate my own risk even lower.
In Ingress, face-to-face encounters with the opposing team are common, although few I would describe as “confrontations.” (Is it a bad sign that it is already “few” in less than two months?) Interfacing through our phones, the character of interactions is somewhere between online gaming and what you might reasonably expect from face-to-face encounters, modified by differing norms in assorted virtual and meatspace communities, particularly as people travel and those interact.
Online, you get a very low number when you multiply the odds that someone would want to do you harm times the odds that they could find you times the odds they would find it worthwhile to travel, risk prosecution, risk harm to themselves, etc. Unless you are in the same gaming cafe, your aggressor faces greater safety risks in traveling than you would from even the most blatant trolling.
If you are actively playing Ingress, your location can be pinpointed within 100 meters, along with a timestamp and a predictable direction of travel based on recent activity. The players may not be marked on the map, but you don’t need to be a genius to follow a line or approximate the center of a circle. And if you are blowing up portals, there is a very good chance someone within reasonable driving distance set them up. And as I have mentioned, some people take the game very seriously, have quick reaction times, and and will bring friends and/or cars. While the vast majority of people are decent and/or scared of repercussions (I am not aware of any Ingress-related violence), your odds on “can find you” and “reasonably close” are vastly higher in an augmented reality game than online.
Recently, any time I have been out playing (attacking, linking, etc.) rather than just hacking as I go for a walk, someone has driven up. Yesterday, I took a low-level player out to gain some levels, and the counterattack SUV was on-scene before we had walked 100 meters. That put her personal risk calculation too high (versus the value of capturing imaginary portals), and she decided to do something else with her day. And given the unhappy reaction from the man who immediately knew that cheating was going on when the lower-level account conveniently disappeared as he arrived, I must say her calculations were probably better than mine.
Update edit: I was wrong, I am aware of one story of Ingress-related battery and a few of minor defacement of property, but I don’t know how well sourced those are. One player says an opposing team member smashed someone’s phone, which is apparently a story well known in the area but doubted by the accused’s teammates. And then folks who put bumper stickers for Team A on Team B’s cars. I recall seeing online discussion mentions of assorted minor criminal activity between Ingress players, but again, I do not know how well sourced those are versus “my friend said his friend said…”