Shipment.cs

public interface IShipmentReadinessRule
{
    bool IsSatisfiedBy(Shipment shipment);
}

public class HasValidDestinationRule : IShipmentReadinessRule
{
    public bool IsSatisfiedBy(Shipment shipment)
    {
        return !string.IsNullOrWhiteSpace(shipment.Destination);
    }
}

public class AllPackagesPackedRule : IShipmentReadinessRule
{
    public bool IsSatisfiedBy(Shipment shipment)
    {
        return shipment.Packages.All(p => p.IsPacked);
    }
}

public class NotAlreadyShippedRule : IShipmentReadinessRule
{
    public bool IsSatisfiedBy(Shipment shipment)
    {
        return shipment.Status != ShipmentStatus.Shipped;
    }
}

public class Shipment
{
    public string Destination { get; init; }
    public ShipmentStatus Status { get; init; }
    public IReadOnlyList<Package> Packages { get; init; }
    public Guid CustomerId { get; private set; }

    public bool CanShip(IEnumerable<IShipmentReadinessRule> rules)
    {
        return rules.All(rule => rule.IsSatisfiedBy(this));
    }
}

public class Example
{
    public bool CanShip(Guid shipmentId)
    {
        var shipment = Db.GetShipment(shipmentId);
        var shipmentRules = Db.GetRulesByCustomer(shipment.CustomerId);

        return shipment.CanShip(shipmentRules);
    }
}