Yes they can. What happened was that instead of always showing every lobby that's open, the game only shows the lobbies for the m,od you're running, so people don't just immediately jopin and desync because they're running the wrong version/mod. There are two causes for not seeing multiplayer games now:
1. There's actually not a game up in the mod you're playing.
2. Your files are different and you never realized it.
The first you can't do anything about except get someone else to play. The second, I made a video on how fix your copy: