No idea if the support request gets resent; I'm betting it doesn't. That said, it's still better to wait for a 2nd RP to generate unless the boss is either quite close to being dead (<1M) or you can reliably deal 1M damage with only 1 RP. RPs regen at 1:30 minutes and RB's last for 2 hours. There's really no reason someone can't wait 30-60m if it means dealing an extra 50% damage.
Remember, there are a lot of players who struggle to hit even 300k (the number all 50 players would need to hit to deal 15M damage total) with 3 RPs, and those are the ones more likely to simply spread tags around since they know their contribution isn't much and have a greater need of the rewards so the risk of some escaping is more acceptable to them. We need to be prepared to make up the slack if we decide to hit the boss.
Now that I'm thinking about it, has anyone ever seen a RB where more than half of the max number of people who could hit it did so? In this event, most of the RB's I've seen escape never had more than 15-ish people hit it.