You can't avoid losses because you can't let goods cross borders without oversight.
The EU has vital interests in controlling the consumer goods available in its market. If we don't have a say in, for example, how they control their food production, we can't just take their word on it.
If you now think, let's just assume the British government does its job correctly in that regard, and we'll be fine, you're wrong. Companies often know which of their products are going to end up in exports, so they know where they don't need to follow the rules.
The EU has vital interests in controlling the consumer goods available in its market. If we don't have a say in, for example, how they control their food production, we can't just take their word on it.
If you now think, let's just assume the British government does its job correctly in that regard, and we'll be fine, you're wrong. Companies often know which of their products are going to end up in exports, so they know where they don't need to follow the rules.