One thing I rarely see (maybe never see) in modern-day fatawa is an indication of doubt in their ruling. As a random example, here's a fatwa about oral sex from AskMufti:
Q: Can a husband or wife perform oral sex on the other spouse?
A: Among other purposes, the mouth has been created for the Zikr of Allah Ta'aala, recitation of Qur'aan, recital of Durood, etc. It has not been created for the purpose mentioned in the question. Sucking of the private organ is an animalistic quality.
Usually during arousal, the organ secretes a fluid called Mazi. This fluid is Najis (impure) and Haraam to take in the mouth. This act must be avoided. Sperm (Mani) is also Najis (impure).
Prepared by: Moulana Yusuf Laher
Checked and approved by: Mufti Siraj Desai
This fatwa does not mention the different views on oral sex (which I surveyed in this answer), nor the different views on semen being impure (FatwaIslam says semen is clean).
Question: Are there modern-day fatawa which say "I don't know" or words to that effect?
The Response (URL) indicates that historically it was normal to express doubt, e.g.:
Abu Hanifa (r.a.) is reported to have claimed: “we [the jurists] realize that this is merely an opinion; yet, it is the best we have been able to reach. If someone produces an opinion better than this, we will accept it”.
Dr. Imam Muhammad Ra’fat Othman