SPC059013: Consider verifying that the user has sufficient permissions when calling WebCollection.Add()

    using (ClientContext context = new ClientContext("http://yoursite"))
    {
        Web web = context.Web;
        WebCreationInformation creation = new WebCreationInformation
        {
            Url = "MySubsiteUrl",
            Title = "My Subsite Title"
        };
        context.Web.Webs.Add(creation);
        context.ExecuteQuery();
    }

    using (ClientContext context = new ClientContext("http://yoursite"))
    {
        Web web = context.Web;

        BasePermissions permissions = new BasePermissions();
        permissions.Set(PermissionKind.ManageSubwebs);

        var permissionResults = web.DoesUserHavePermissions(permissions);
        context.ExecuteQuery();

        if (permissionResults.Value)
        {
            WebCreationInformation creation = new WebCreationInformation
            {
                Url = "My New Subsite",
                Title = "My Subsite Title"
            };
            context.Web.Webs.Add(creation);
            context.ExecuteQuery();
        }
    }