Chopping Blinds - Time rakes?

[Lurshy]

With rakes coming out of each pot on the flop it is easy to understand why people chop blinds on those rare occasions with an opportunity to do so. I do so consistently.

This weekend I was playing 10-20 limit @ the Borgata which has a 5$/half-hour flat rake.

I was surprised to see everyone chopping blinds. I didn't say anything, but this was counter intuitive. With no house commission on each pot it not like you will earn back less than you risk if you win.

Is chopping at higher limits with time rakes customary? and why?

Thanks,
Lurshy