TBH it's not like you can't help your friend.
If your team is keen in helping your friend(s), you can schedule your raid to a Sunday or even a Monday, clear them all in a single night.
Then from Tuesday to Saturday you can bring your friend(s) in and teach them how to play all the way to the last 5% and intentionally wipe it.
Your raid could split into equal 2 halfs and bring in another raid in 2 halfs to form 2 training raids easily.
So it's not like there isn't a way to train or help your friends with what they need to learn and practice. Given that there is a way to do so, there isn't a reason for SE to do something extra to mitigate the risk or cons that they aren't keen in giving in.
All in all, it comes down on whether you want to do it or not. I have met players who does that. I came to know some great guys from FFXIV Guild on Tonberry server and they brought me in to practice T9 despite me telling them I have no experience at all and would just wipe them (they were practising divebombs at that point in time).
Well, I accepted the offer, and in approximately 3-4 hours I'm pretty familiarized with phase 1 - 3. Still dying on T4 thou but that's another matter. I learnt a great deal there and from them and with that experience and strategies, the logic behind them learnt, I bring back to my raid and now I'm guiding them to pass Heavensfall and we can progress on Divebombs together or something.
The same thing can happen to any FC. If you really had the heart to help, hold on the urge to rush for the clear and loots, bring some guys in to practice and eventually they can do the same thing and pass down the knowledge and experience down the line.
