In the case of specific individuals who had done notable things yes. Most of the time these led to some conversations and I interviewed them to gain a sense of their in-game persona to ensure I could represent it in Premonition - I don't recall any that did not want to be included. In the case of player groups, I made an attempt to. Some did have representatives which I could speak to, but some did not and some did not respond - particularly the more 'controversial' groups. Since my brief was to represent "Elite Dangerous" as I saw it, they went in anyway.
Technically it wasn't illegal or an IP violation for me to use "Harry Potter" in Premonition, but I decided that it wasn't appropriate given it being a SF franchise and, in discussion with Mr. Potter, we agreed on "Beseiger".
Otherwise, names, characters, businesses, player groups, places, events and incidents are either the products of the author’s imagination or used in a fictitious manner. Any resemblance to actual persons, living or dead, or actual events is purely coincidental. No Trumbles were harmed in the writing of these books.