Agree with WJ that you definitely want to avoid the spray given the recent deaths. That said, I disagree that ants are ubiquitous in BKK hotels. Since I started coming to BKK in 2006, I've stayed at Landmark, President Solitaire, Ratchada Suites, CitiChic, Grand Millennium Sukhumvit, LM, PA and SGS. Never seen an ant in my room. Not a single one.