He used to dislike making conditional stipulations during the Hajj and would say, "Is the practice of your Prophet ﷺ not enough for you? He did not stipulate any condition."
حدثنا عبد الرزاق أخبرنا معمر عن الزهري عن سالم
أنه كان يكره الاشتراط في الحج ويقول أما حسبكم سنة نبيكم ﷺ إنه لم يشترط
Its isnad is sahih. Tirmidhi (2:117) narrated it through Abdullah bin Mubarak, from Maamar, and said, a hasan sahih hadith. Bukhari (4:7-8) narrated it at length through Abdullah bin Mubarak, from Yunus and Maamar, both from Zuhri. Hafiz in al-Fath also attributed it to Daraqutni, Ismaili, Abdul-Razzaq, and Nasai. Ibn Umar, by this, is pointing to a rejection of what Ibn Abbas used to give as a legal opinion, namely the permissibility of making a stipulation. The permissibility of it is established from the hadith of Ibn Abbas in the story of Dubaa bint Zubayr, as has passed at 3117 and 3302, and the story of Dubaa in that regard is also established from the hadith of Ayesha in the two Sahihs, and from the hadith of Dubaa herself as recorded by Ahmad. See al-Fath (4:7) and al-Muntaqa (2376-2387). For that reason Bayhaqi said, as quoted in al-Fath, "Had the hadith of Dubaa concerning the stipulation reached Ibn Umar, he would have held that view."