The more I think about this, the more i'm just not sure if LIDL actually are bu.
To put another slant on it - I live in S Wales. Welsh isn't particularly common down here (as opposed to the further North you go) but I still know a fair few Welsh speakers who are fluent, went to a Welsh school etc. I understand it at a novice level and can throw in a few sentences, but would struggle to understand a full-blown conversation.
I have two Welsh speakers on my team who speak to each other in Welsh. They do it more for a 'use it or lose it' reason because they're in the minority, and they switch easily back and forth to English when needed. I don't mind at all - because they're two on a team of 14, so no one is particularly left out, there are plenty of us who can't join in. As part of their job these two are required to speak to customers in Welsh if someone requests a Welsh speaker.
However, if 12 out of the 14 on my team were all Welsh speakers and all were talking in Welsh on breaks and lunches, I can imagine that would get very tiresome for the ones that didn't understand...and from a childish pov, i'd probably feel quite left out paranoid if I never understood the conversation around me.
^If this was my work and by chance Welsh was being spoken by the majority, I actually think my employer would be reasonable in suggesting to Welsh speakers that they use English instead to promote a good team environment and all the rest. Even though we're in Wales. No Xenophobia there...just common sense.
I can't really see a difference between this and LIDL, so on the whole i'd say LIDL are not bu.