Many conditions and activities are studied with EEG. For example, trying to predict epilepsy, sickle cell, creativity. My son and I have dreadlocks. I am a scientist in public health (outcomes research). I play in both a jazz band and steel pan (drum) group. I am a long time SAS user (mostly SAS/STATS). I have had a successful Fulbright Scholarship. My interest and activities indicate that I am at least proficient in quantitative and 'creative' areas. My son plays guitar, enjoys classical music and dub step. He's planning to pursue an MD/PhD in radiation oncology. However, I am not sure that the surface or swim cap electrodes would capture our brain activity clearly. Imagine if an AI algorithm was being used to map and score our brain activity for an important role. We might score low (if at all). Our cultural heritage would not be subsumed in the training data. Dreadlocks are not just coarse of curly hair. Dreadlocks is more like wearing a turban. While a turban (in principle) can be removed for the investigation, dreadlocks can't be taken off and put back on.
I don't know what is a fair solution. I do know asking us to cut off our dreadlocks is not an equitable solution.