Radio Frequency Interference or RFI causes problems with all valid and approved radio based devices and prevent them from work at their best or worse not at all. People who use radio products expect them to work. To guarantee that can happen, governing agencies are needed.
GOVERNMENT REGULATION
To allow people to enjoy the proper operation of devices using radio frequencies, the government has set up agencies to govern the usage of the radio frequencies. They are charged with the enforcement of the usage of the radio frequencies and can penalize companies that make any product that causes levels of unacceptable RFI to be generated. The requirements for a RFI filter varies both with the country it is sold into and the type of product it is. If it is required, it is the company’s responsibility to put is suitable measures to prevent EMI generation which is most often addressed by using a RFI filter circuit. If a product sold fail to meet the RFI requirement, the company selling it can have the product forcibly removed from the shelvs of all the stores and pay a major fine for not complying.
USA VERSUS EUROPEAN REGULATION
In the United States, the FCC control the radio frequencies. In Europe, the BEREC performs the same function. The BEREC standards are more stringent compared to the US and other countries and as a consequence forces EMI filtering to be installed on motor in order for the product to be sold in the EU.
SELLING PRODUCTS WORLDWIDE
Companies like Bachmann want to sell one version of it products world wide. It keeps the cost down. To them it is simpler to go ahead and add a capacitor/RFI filter to meet the most demanding country requirement so there are no restrictions on what is sold where. This can have higher priority than the potential for creating functional consequences when working with high end DCC decoders.