While I love playing on Roll20 as someone still getting their feet wet in tabletop gaming, I do have this suggestion. So far, the only way I've seen to make sure that someone has sent a message with a link to the game or information prior to it has been a case of refreshing the page to see if there's a notification or paying close attention to when a message pops up in the corner. What if we get distracted by something else like a phone call or something?
What I suggest is being like some other forums and allowing the player to receive an email to just basically say "Hey, you have a message waiting for you on Roll20." or something to that extent. This can also be applied to any threads you're following in case the GM has some information to share like a change in players or a new time or whatever. I think something like that may just help some players from accidentally forgetting when a game is about to start or if the GM has something important to say.
