Guardianships and powers of attorney are somewhat similar in that they allow someone else to sign documents on behalf of another, but there are some key differences between them that you should keep in mind. Most importantly, a guardian is appointed by the court for someone who lacks the legal capacity to enter into a binding agreement (among other things), while a power of attorney is a document by which someone voluntarily allows another to make certain decisions on their behalf.
When running title, if you find a document by which the mineral owner’s attorney-in-fact conveyed an interest, you should also include in your abstract the power of attorney by which he/she received the authority to do so. On the leasing side of things, if your lease or other agreement was signed by an attorney-in-fact, then you should make sure the power of attorney is filed in the county where the land is located. If it was not recorded there, it is a good practice to request the POA and record it yourself before recording the lease. As always however, first check with your manager, in order to find out how your company/client would like you to proceed in that situation.