I also don't think it's a good idea to mix diclofenac and alcohol. There is already a risk of stomach ulcers with this medication and everyone knows that alcohol is hard on the stomach.
Also, if you're taking the mediation for chronic pain relief, alcohol is probably going to make it less effective. Either don't take the medication if you're going to drink or don't drink if you're going to take the medication.
We all are responsible for our own health and need to make informed decisions when it comes to these things.