Making undeclared cash payments to tradesman is one of the reasons Spain and Greece is in the financial state it is. It’s immoral, illegal and criminal behaviour. You cannot simple condone it to yourself by saying ‘that’s what people do in Spain’.
What happened to moral courage and trying to make a difference Rocker? Shame on you. 👿
If you tried that in France the Gendarmes would feel your collar and most French tradesman I know would give you a stern lecture for even suggesting it.