Emergency departments (EDs) serve as the front line when patients encounter the hospital system. Limited data are available of patients' alcohol habits collected during Danish ED visits, and no studies have, to our knowledge, examined frontline staffs' (registered nurses and medical secretaries) acceptability to deliver anonymous alcohol surveys to patients. We aimed at examining the proportion of survey respondents and the prevalence of patients' alcohol habits and also exploring frontline staff acceptability of the distribution of an anonymous survey regarding patients' alcohol habits in EDs. Intendedly, all eligible patients ≥18 years old entering two EDs in March 2019 should receive a survey based on the Alcohol Use Disorder Identification Test. The study was an explanatory, sequential, mixed methods design, and results were analyzed with descriptive statistics and a deductive content analysis based on the theoretical framework of acceptability. In total, 15% (n = 1,305) of the total 8,679 patients in the EDs returned the survey. Qualitative analysis of interviews (n = 31) with staff showed that they had been reluctant to distribute the survey primarily because of ethical concerns of anonymity, freedom of choice, and being nonjudgmental toward patients. Hence, patients with no obvious alcohol problems were more likely to receive the survey. Still, we found that 23% of the respondents had an Alcohol Use Disorder Identification Test score ≥ 8. Results indicate that frontline staffs' recognition of patients' alcohol use is inadequate, and findings show a low degree of acceptability among staff to deliver an anonymous survey, which is in line with earlier described barriers toward screening activities in EDs.