Restriction to society Terrace access & activities

Due to lockdown, my society had allowed terrace access. However, there are people who hangout on terrace late night and secretly have alcohol consumption and smoking. I had seen them hiding alcohol and heading to terrace. Also, there had been a mischievous Behivaour where ISP cable was removed and through at midnight for one of the tenant by these people. We are allowed wfh by company & ISP is bread butter in wfh. They had raised this complaint to manager, but no action taken . Still these people move in the terrace and have secret activities of drinking & smoking. I had raised a concern to manager of society about these things happening. He has a suggestion rater to keep terrace open all day, so that we can observe their behaviour. But this doesn't make sense. It's an open space and people can drink smoke , party at these place. Also it's a safety & privacy concern for owners for people on terrace at midnight. Touchwood of any offense could happen at midnight. I want your suggestions on this so that we have a decent living in society.