Is it a bad idea to share my XPub?
99.9% of the time it is a bad idea because you wouldn’t want someone to track your Bitcoin activity.
However, sharing your XPub allows your donor to know 100% for sure you are not spending your savings.
When you are done with the program, you can simply move your Bitcoin to a new wallet and your donor will no longer see your Bitcoin activity.
*Sharing an XPub sets off alarm bells in most Bitcoiners as it is known to be bad for privacy.
**After many discussions I have not heard a way a malicious donor could harm a saver.
***I am continuing to talk to more Bitcoiners, if a saver can be damaged, this program will be abandoned.