You don't know it will be used for illegal purposes, unless they explicitly tell you so. Otherwise, if you assume they will be used for illegal activities, for

You don't know it will be used for illegal purposes, unless they explicitly tell you so. Otherwise, if you assume they will be used for illegal activities, for instance based on the appearance and behavior of the owner, you are discriminating and can be sued for that. If you refuse someone service because he's black, you are wrong. If you refuse someone service because you think he's a criminal, you are wrong again. If you provide someone service despite thinking he may be a criminal, you are also wrong. It's a lose-lose situation. Best not offer services that may be used for criminal activities. /s