Overstayed 4 years,

I hope someone can give me an insight?
I had it broken to me that someone I’m very close to has been in the uk illegally for the last 4 years and entrance to the u.k was gained using a false identity... she is Romanian and with the recent acceptance to the EU i'm hoping leaving and re-entering won't be a to much of a problem???
Her legitimate passport has expired so I’m assuming a trip to the Romanian embassy is in order to gain a travel document??? Is there a risk when applying for the travel document??? What problems could arise when leaving??? What are the penalties if caught???

Thank you for your thought and time...

Since Romania is now a part of the EU, perhaps regularisation might apply. I don't know honestly. I would suggest digging something out from the IND website about it. There must be some new information over there about any irregular migrants from the countries that are now part of the EU.