This is very likely a mistake by UTG thinking it was a $2 chip. Or a false tell kind of thing if UTG had the nuts and wanted a caller. Not that it matters to the resulting decision but it would be good to know if the $100 was in a $2 chip stack or by itself on the felt. I doubt there was a stack of $100 chips and it came from there.
As is noted above by everybody, this is always going to be ruled a $100 bet.
I play a lot of tournament poker and the chip colors in every casino are different. I was in Prague for a year and I played in tournaments regularly at Rebuy Stars Casino Luka. I then went to King's casino in Prague and played and accidentally put a 5,000 in what I intended to be a 800 bet. So my bet was 5,300. I knew that no matter what I said my pre-flop raise was going to be 5,300 so I said nothing. A guy called me with K8o and then called my 5,300 flop cbet when he hit an 8. We checked it down after that and he won. Sad for me.
Then it happened at Rebuy Stars when I was the BB. I accidentally put 2 calling chips out to get change which means that I raised so I had to fold when my opponent re-raised. I looked at the dealer who I knew and he said "sorry it has to be a raise" basically regardless of my intentions.
Then either yesterday or 2 days ago in a tournament (at either Mohegan Sun or Foxwoods) a woman put out a 10,100 pre-flop raise on the first level. We all folded but that couldn't have been intentional and if somebody had said "raise" and then jammed I would guess there would have been a discussion that she would have lost.
One last incident. In the WSOP Main event Day 1D a few years ago somebody bet like 1300 on a flop and a guy put out 10,300 chip raise. The 1300 guy folded. After the hand I asked the guy if he knew that he had put out two 5,000 chips (was he color blind?) and he basically didn't want to answer but after a while said he wasn't color blind. About 30 minutes later I raised pre-flop to 1,200 on the BTN and SB called and the maybe color blind BB called. I had A5s. Flop was A
Q
5
and it went check check and I bet 1,200, SB folded and BB raised to 10,200. I thought about it and decided to just call. I almost folded because I thought it had to be intentional but also thought he was unlikely to have AQ/QQ/AA without re-raising pre-flop (wow was I wrong about that) and there was only 1 combo of 55 and that he could have a flush draw with or without the A
and was messing with me on the sizing so I would fold... He bet 8,000 on a non-spade turn and 7,000 on a non-spade river and I just called both. Fortunately neither was a K or Q or whatever the turn was and I beat A
K
. Not that I cashed.