You can tell when they are negotiating time instead of scope. It will be something like "surely we can do this in 2 days not 5?" Instead of "we probably will take 2-5 days to do this but need it in 2 so something of 3 days needs to come out somewhere else". The first one is saying 'work harder and just do it.' The second is 'ok it may take 2-5 days but lets pull something else out to make up for the deadline we want'.

I found orgs that negotiate time did not talk to their team in the first place. Then went on to promise something on behalf of the team. Now they do not want to eat the humble pie of 'I ran the numbers and you only get half' instead they get it going and just overbudget on the thing. Which just makes everyone in the process mad.