Assuming we're happy that the question isn't asking about some illicit synthesis where laws are clearly being broken (*), then I see no reason why chemistry.se has any more of a responsibility/duty of care towards the person asking the question than any other resource on the internet.
Chemistry journals are full of procedures which are likely to cause harm in the hands of a junior chemist/without careful consideration, yet articles/supporting information documents rarely detail safety hazards/precautions, unless the hazard was particularly unexpected or out of the ordinary. (That said, I'd accept that journals are generally written by experienced chemists, where as on chemistry.SE there is an element/possibility of the 'blind leading the blind', that is inexperienced chemists/non-chemists/old-school chemists offering practical advice to other inexperienced chemists who don't know better).
If we do feel the need to police these sorts of questions, then perhaps the most productive thing would be to adopt an 'org syn' style disclaimer, basically telling the person asking the question to not take the response at face value but rather consider the implications of what they're being told to do (see below).
I'm not sure how this could be implemented; either as part of the T&C's during signup, or perhaps something the mod's could tag to specific posts related to practical chemistry.
The procedures in Organic Syntheses are intended for use only by persons with proper training in experimental organic chemistry. All hazardous materials should be handled using the standard procedures for work with chemicals described in references such as "Prudent Practices in the Laboratory" (The National Academies Press, Washington, D.C., 2011; the full text can be accessed free of charge at http://www.nap.edu/catalog.php?record_id=12654). All chemical waste should be disposed of in accordance with local regulations. For general guidelines for the management of chemical waste, see Chapter 8 of Prudent Practices.
In some articles in Organic Syntheses, chemical-specific hazards are highlighted in red "Caution Notes" within a procedure. It is important to recognize that the absence of a caution note does not imply that no significant hazards are associated with the chemicals involved in that procedure. Prior to performing a reaction, a thorough risk assessment should be carried out that includes a review of the potential hazards associated with each chemical and experimental operation on the scale that is planned for the procedure. Guidelines for carrying out a risk assessment and for analyzing the hazards associated with chemicals can be found in Chapter 4 of Prudent Practices.
The procedures described in Organic Syntheses are provided as published and are conducted at one's own risk. Organic Syntheses, Inc., its Editors, and its Board of Directors do not warrant or guarantee the safety of individuals using these procedures and hereby disclaim any liability for any injuries or damages claimed to have resulted from or related in any way to the procedures herein.
(*) It's often very clear when people are asking about drug syntheses due to the very specific nature of the chemicals involved. In these cases I fully agree that answering is counter productive anyway, irrespective of safety.