Yekke and DY,
1. The Rema says that the “only” reason for having to return it is kiddush Hashem. Is that light in your eyes? May one compel a fellow Jew to do a kiddush Hashem?
2. Rav Menashe Klein disagrees with the Netivot ( <a href=”http://www.hebrewbooks.org/pdfpager.aspx?req=1878&st=%d7%92%d7%96%d7%9c&pgnum=373
“>Mishna Halachot 6:305)). This is also the view of Rav Ovadia (הלכה ליום רביעי כ”ט טבת תשע”ד). In any case, the Netivot himself says that the thief must pay for the object.
3. The Chatam Sofer says (v. 6 Sukka 30) that the Rambam holds that one must return the object.
4. See also Yerushalmi Baba Kama 4:1 and Biur HaGra EH 28:5.
5. You have not addressed by citation of the Meiri nor have you addressed my other points.