We rarely, if ever, encounter someone in the arena who is lagging so badly that it actually requires staff to intervene. That's usually because they'll end up disconnecting or freezing for an auto loss. People like Jimbo and Volkan are probably some of the laggiest sparrers and we just deal with it.
I don't think any active sparrer has it on their list of priorities to find opportunities where they should lag themselves for an "advantage." It's so much more likely that they're getting bad service, a family member is using their internet, or their ISP is just choking for a few minutes or seconds. It's happened to me before, and it's more of a punishment to me than anyone else. That being said, I don't think that's worth punishing with a ban...