People prefer altruism in others when it appears to be due to a personality characteristic rather than overt reputational concerns; simply pointing out that there are reputational benefits of action may reduce them.
pˈiːpəl pɹɪfˈɜːɹ ˈɔːltɹuːˌɪzəm ɪn ˈʌðɚz wɛn ɪɾ ɐpˈɪɹz təbi dˈuː tʊ ɐ pˌɜːsənˈælᵻɾi kˌæɹɪktɚɹˈɪstɪk ɹˈæðɚ ðɐn oʊvˈɜːt ɹˌɛpjuːtˈeɪʃənəl kənsˈɜːnz; sˈɪmpli pˈɔɪntɪŋ ˈaʊt ðæt ðɛɹˌɑːɹ ɹˌɛpjuːtˈeɪʃənəl bˈɛnɪfˌɪts ʌv ˈækʃən mˈeɪ ɹᵻdˈuːs ðˌɛm.