It depends on the company, or more specifically on how the company manages the budget (people working on projects, infrastructure budgets, etc.). In many companies people would rather do the other way around: inflate their estimates to make sure that they definitely fit the reality later. This also often leads to continuously increasing budgets because or the corporate logic: “if you asked for budget but didn't use, then why did you ask for it’? So people would be actively looking for ways to spend any excess, to make sure that next time they will be trusted with their estimate, which in turn would likely be bigger than the previous one. Crazy, but true.

So, it can work both ways really.