Among Kenyan Christians, the distinction between the terms 'church member' and 'visitor' is widely used, and occasional visits to non-membership churches are a common practice. In our ethnographic research in urban Kenya (Nairobi and Kisumu), we observed how, across denominations, church visits abide by similar, formalized, and ritualized codes. Through an analysis of the subtleties of this institutionalized practice, we expose a fundamental tension in which even as church leaders are expected to act in the spirit of Christian unity and avoid proselytizing visitors from other churches, they also seek to maximize the use of church visits as an effective instrument for recruiting new members. Investigating how churches manage this 'sheep-stealing dilemma', we analyze some institutional strategies that favour membership retention and attraction without formally undermining the social legitimacy of church visits.