If a deed of transfer for a piece of property or other item indicates that the only consideration is "love and affection," there is a likely relationship between the seller and buyer on the property. In fact, it might not even be technically correct to refer to the grantee as as buyer. On these deeds the relationship among the parties is not always stated.
Similarly, if the amount of the consideration on a deed is a token amount, say a "dollar," that also might be a clue as to a potential relationship between the individuals involved.
Deeds that say a "dollar and other valuable consideration" may be referring to a mortgage or other document also recorded on the property.