Hi. Most of the poker streamers seem to stream with a delay in the 3 minute to 5 minute range. Which is usually long enough to ensure that any given hand is over before it is broadcast on the stream. If a hand takes an extra long amount of time it's possible if someone in the hand is watching the stream they will be able to see the streamer's hole cards while the hand is still going.
It doesn't happen that often but every once in a while a streamer will cut the stream if they think they are being sniped and restart with a longer delay.
Sniping and ghosting are both streamer terminology to describe when a player is in-game with the streamer and the player is watching the stream to gain an unfair advantage in that particular game.