I received this when I wanted to post into a thread after starting two myself this morning.
I assume I have managed to miss the thread that would have explained why this was now forum policy. Could someone post a link to it? I can assure you that this is not a spurious request as I have looked in the Forum rules and can find no mention of it.
But it seems odd that you are being restricted to helping two people once,or one person twice in a 60 minute period. Something I have never come across before.
Any reasonable step, and this is reasonable, to keep spammers at bay is fine by me. Anyway, at my average of 17.06 threads per year, it's not going to have any significant impact on my thread posting habits!