It's very common for games to deal with erratic input from keyboard controls. Consider player position in a moba or fps where two humans are responding to each

It's very common for games to deal with erratic input from keyboard controls. Consider player position in a moba or fps where two humans are responding to each others' presence (footsie.) The penalty for a wrong prediction is rubber banding, so if you can get away with streaming their past at high latency, I would avoid predicting at all. That's the model often used by async PvE games (think social games, invest/express, etc) and I think that approach would map best onto SaaS presence features.