Policies should be part of your Quality System. You can create policies for your business using policy templates.
Don't risk drugs and alcohol in your small business. The last thing you want is drugs and alcohol destroying all your hard work. Use a policy and educate your team about the rules and expectations in your business.
The internet is a scary place. Yeah - we all know how good it is and also how potentially bad it is as well. Do you really want to invite the 'bad apples' into your business? Not likely I would say.