In real life, people are more relaxed and you’re not siocially ostracised because you DIDNT being the right thing or DID bring the wrong thing.
To be honest, at a reasonably busy BBQ who has time to notice much and who dwells on it after the event? Clearly some on here.
When we’ve hosted, some people ask if they can bring anything. I usually say no need, or if it’s a big event might suggest some drink or something simple like a salad. Sometimes those people then bring that item but often they don’t or bring something else. Others don’t ask if they can bring anything but do..could be food or drink of any description. Others come empty handed. All are fine.
When catering, unless I’ve had an explicit conversation with someone that they will definitely bring X, I plan to provide all the food...otherwise, you can find yourself without a crucial item. Anything else anyone brings is an extra bonus item.
If I’m going to a BBQ or similar, I’d ask if Incould bring anything and unless we had an explicit conversation I’d take any reply as a suggestion and might then take that item or not. I would pretty much always take some drinks and a food item, even if it was not some big bags of crisps or snacks.
BBQs can vary a lot. For larger BBQs people hosting often ask people to bring their own meat. Someone in another thread was offended by this. I’ve been to BBQs for 30-50 people and that’s worked really well...massive BBQ and everyone’s meat is at the side and people eat some of their own and share too. You take an amount for your family and some extras. The host normally provides some salads and bread and puddings. As BBQs by nature are informal, it seems fine.
I’m happy to be invited and asked to bring meat or to bring a salad or a dessert or not asked to bring anything. Why get bothered by such things. Just go and enjoy the company and realise there are many different ways to host these things.