All right, folks, here's the deal with traps in 1.10.
Traps are not "visible" in 1.10. However, they're no longer invisible, either. Traps are now considered stealthed, with the detection that implies.
Considering the radius on Hunter traps, this should not affect PvP gameplay as much as, say, visible traps would. While they will appear to those who get close, there's still a very good chance that players will trigger the trap regardless.
The developers are open to examining the radius of trap detection and may change it depending on how it plays. I simply wanted to dispel the rumor that traps are visible to everyone, when that simply isn't the case.
It's a general trap change that will allow for moredynamics in PvP and in general gameplay in the future, basically,rather than being strictly invisible.