How Accurate are These Royal Lines

[Ánleifr]

Hi, I ran across this pedigree (family tree chart) the other day and if you expand each of the 4 different branches (Lucy, Hugford, de Grey and Roos) you will see that they each turn into a Pandora's box of multiple royal lineages. Some of them even overlap, is this typical with the elite only marrying elite and can anyone with some British Isles history/knowledge take a look at these lines and tell me if this tree is correct?

http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=PED&db=ancestorsearch&id=I42750&style=TABLE


Thanks.