The ruling on stoning the pillars with pebbles found near the pillars

This was sent to us, or this message reached us from the outskirts of al-Dawadimi from 'Abd Allah al-'Utaibi, and he specifically addressed your eminence, saying in it: I inform you that I performed Hajj for the first time, the obligatory pilgrimage, and when I came to stone the pillars on the second day, I stoned in one pillar, in one station, and when the pebbles with me, the two [sets], were finished, I repeated and took from the gravel under people's feet at the edge of the pillar, and stoned with it in the other stations. Please inform us, may Allah reward you with the best reward, what is upon me? And what should I do, since I stoned with them while forgetting? And to you abundant peace?
Answer: There is nothing wrong, if Allah wills, it suffices. If a person stones with the pebbles found in the road, or under people's feet, it suffices, if Allah wills. As for taking them from far away, that is more cautious and better, otherwise it is sufficient; because the original state is that they were not stoned with, they may have fallen from people, or a person may have stoned with them and they did not hit, so the result is that there is no certainty that they were stoned with, rather it is possible, so they are sufficient. Then, the statement that what has been stoned with does not suffice is a statement based on independent legal reasoning, not based on an explicit text from the Prophet (peace and blessings be upon him). So, avoiding what has been stoned with is undoubtedly more preferable, not stoning with it. As for something under people's feet, one does not conclude that it has been stoned with, so it is sufficient in any case, and stoning with it, if Allah wills, has occurred in its proper place. And if there is a choice, it is more preferable for him to take a stone far from the pillars in places far from the pillars, so that it is further from having been stoned with. This is the more cautious and better option.
The presenter: But if he takes from under people's feet, this ...?
The Shaykh: It suffices, if Allah wills, it suffices, and it is not concluded that it has been stoned with. Yes.
The presenter: Many students of knowledge forbid people strongly from that?
The Shaykh: This is not good, it is not good, it is not befitting to be strict in this. Yes.