Transit Police report arresting John Bubier, 60, around 9 a.m. today at Andrew Square after officers say they watched him piggyback through a fare gate behind a paying T rider and then discovered he had failed to register as a Level 3 sex offender.

Bubier, originally from Framingham, but best known for his croaking pleas for change in Downtown Crossing, was convicted of indecent assault and battery in 2011.

Just yesterday, Bubier appeared in Boston Municipal Court to answer to a probation violation after a recent arrest for disturbing the peace in Chelsea. The judge let him free until a September hearing on the matter.

Innocent, etc.