You are deluded if you think they can trespass into Bangladesh without anyone noticing.For more then 4 decades, Rohingyas were subjected to most extreme form of persecution and deprivation in Rakhine.But Rohingyas could not entered Bangladesh unless we let them into.Now preventing any infiltration from assam will be much easy.Thanks to Indian govt. for putting barbed wire fencing along much of BD-India border.With biometric NID card in places, no foreigners can disguise as citizen in Bangladesh.Even if any stateless Indian manage to come into Bangladesh, he will find life in Bangladesh much harder for him then in India.So he will smuggle himself back into India in a short notice.