Anatomy of a Calling Station

Live riverchasers freeroll, level 3 (3/6, T200 starting stacks).

UTG raises 15 to 21. <---- first hand played in 1/2 hour
SB calls 18.
BB folds.
Flop [T 8 4] rainbow.
SB bets 20.
UTG calls 20.
Turn [A].
SB checks.
UTG bets 25.
SB calls 25.
River [K].
SB checks.
UTG bets 50.
SB calls 50.

UTG shows [TT] for three of a kind, tens.
SB shows [JJ] for a pair of jacks.

Is there ANY reasonable holding UTG could have that justifies the turn call, and especially the river call?

Sadly, that was, by far, the best hand I saw all night and one of only two pots I won. I tried to use my image to get stealy a couple times on semi-bluffs, but kept getting called down or raised and had to release. Steady diet of 75o and J2o isn't real helpful against these types of players. And still, I outlasted 2/3 of the field.

Vegas - one month from today. Tick tick tick tick....