The ruling on fragrant perfume for the one in ihram

Question:
Ibn 'Umar would apply an oil that had no scent?

Answer:
As far as he knew about perfume, he thought it was not prescribed.
The principle is that the one who memorizes is preferred over the one who does not. The one who memorizes the Sunnah is a proof against those who did not memorize, among the Companions and those after them. So Aishah memorized it, and Ibn 'Umar did not memorize this matter, so she is preferred, and she directly experienced this matter.
The principle is also that the one who affirms is preferred over the one who denies.
Q: He considers it prohibited, meaning?
A: He considers it not permissible, after entering into ihram.
Q: Some people exaggerate with perfume before they enter ihram, so when they become in ihram, they are saturated with a lot of it?
A: It does no harm, it does no harm, as long as he did not intentionally apply perfume, nothing happens.