SB wants to bet after 3 checks behind him

[punkass]

I was at the Borgata this past Friday-Sunday. I played 10/20 2-way for about an hour (omaha HL / stud 8). Slowest game ever.

Anyways. It's a half kill Omaha hand. It gets 5 way capped. Flop comes down 577. I don't see the SB do anything. Dealer looks at middle position player, implying it's his action. MP checks, MP+1 checks, button checks. The checks were not bang-bang-bang, but they weren't slow either. SB puts out 15 dollars. Shouting ensues.

"You checked!"
"I didn't check!"
"You can't bet after we checked!"
"I can bet since I didn't check!"

blah blah blah blah. The whole argument and floor decision takes 15 minutes to clear, which isn't too bad since at this game means I only missed 2 or 3 hands. I will never play this game again.

What say floor?