You can still wire off sandbags, but it takes some more effort:
- You can place wire 2-deep while making sure they're far enough apart to not provide cover, while also making sure the enemy can't slip through the gaps and your units don't get trapped.
- You can place a single vertical wire if you're stretched for time. This will deny some of the cover spots and make it easier to flank. It doesn't carry as many any of the risks as 2-deep wire and you can always follow-up with more vertical wires later on to fully deny the cover