when Rb Pinchos Kohn and Rb Binyamin Carlebach went to the Gerrer tisch during the First World War the Gerrer rebbe said – bring a knife and a fork for the Deutsche.
This is a raayah berurah she’ein alav teshuvah that if someone with a non-yekkishe minhag visits a yekkishe household that they should be catered for