first place? There is a reason coaches have sign shields so the All 22 camera that coaches use don't show the signs.
Now though, with comms in the helmets, signs are used very rarely, or not used to the degree of calling the overall play. So even if a team has learned another team's signs in the past, they would be even more reactionary to what is happening on the field. Which brings up why teams like Utah almost walk a guy off and onto the field during a late sub. They do this not just to waste time, but so they can examine the alignment of the other team. Almost always the guy coming in already knows his assignment, and it is a measly bull rush, everyone else is watching the defensive coaches for adjustments