Among the first things that most people who go out in the work of Da'wah and Tabligh learn is the stories of Sahabah and their cautiousness and abstinence from doubtful sources of food and income. Along with that, they're encouraged to respect all tablighi Ulamaa', but take matters of law from such Ulamaa' who go in tabligh. So in essence a person who takes these principles from Tabligh will be very cautious about those matters and most likely take fataawaa from tablighi sources.