What if you deleted the email you sent saying "Please ensure the crane you are using is rated for that load" and you need it when you get prosecuted by health a

What if you deleted the email you sent saying "Please ensure the crane you are using is rated for that load" and you need it when you get prosecuted by health and safety for the horrible accident that just happened. EDIT: Or the email saying "Yes you can carry out the work in the manner you proposed but only if it will be at no extra cost to my client and you take full responsibility for the alteration to the original design"