Seat jumping is fairly easy to do at the Ricoh given the number of spare seats and the fact the under stand concourse gives access to the East, West and North stands. I'm not sure what the stewards can do about it, and whether Wasps are even aware of it
I thought the South stand was cut-off from the rest of the concourse though so once in there, you can't access halfway line seats elsewhere.
What's slightly confusing about the Worcester 4, is that they appear to be almost on the halfway line. The Wuss stand won't have as many free/spare seats for someone to jump into, let alone 4 all together in the main stand on the halfway line.