If you can get your clients to go along with the waiver language, it's a good idea to do so. Remember, your GL policy has set limits--so avoiding claims that would serve to exhaust that limit, where you can, is a very good idea. Also remember that a GL policy has exclusions--one notable one being for professional liability. If you are providing any kind of professional or consulting service, you have a liability exposure that will not be covered by a GL policy--you need a separate Professional Liability policy for that.

Same thing goes for Workers Compensation liability, of course--no other insurance covers for your Workers Compensation liability (and Employers Liability as well). Only a WC policy can insure you for that. A GL policy contains specific exclusions for both WC and professional liability.