It must have been a massive fluke to be honest as I have family in Liverpool & I have done that journey countless times & I have always been checked on the train & before boarding at Euston.
I walked past the staff onto the platform at Euston on the Saturday morning & they just waived me...
No one checked my ticket getting on at Euston on the way to the Everton game, no one checked on the way & Lime Street has no gates. This happened on the way home as well.
Worth a try maybe ..... ����*♀️