One of the tasks I have absolutely dreaded over the course of my business career is the annual forecast. It would save everyone a lot of bother if the executive in charge would just state the number that will give him his bonus and be done with it. But instead there is a big kabuki theater of staff doing market analysis, market inputs, competitive analysis, inflation and currency trends, and creating giant spreadsheets of models that generate a number. Then the executive then says "too high" or "too low", a few variables are tweaked, and the model generates the number desired.
In my 25 plus years of business I have never seen an accurate business forecast. They were either cooked (revenue already signed and in the bag, then the model tweaked to match the sales manager's give-me), sandbagged (forecast put waaaay below the number the sales manager knew he could hit so it would be a slam dunk), or totally optimistic forecasts that everyone knew was impossible, but presented to executives so everyone knew they had time to interview before everything fell apart.
I have been in several situations when things were definitely going to be bleak 12 months later - no question about it - but didn't end up in the forecast. A flat or slightly up forecast was presented and everyone hung on 9-12 more months until the truth was out. The forecast-lie was sort of an extended layoff package for those in the know.
Sandbagging is my usual tactic if things are not bleak. I might have contracts lining up for $80M, but forecast $60M. This gives the sales team wiggle room for contingencies, but makes everyone look good when the forecast is blown out.
Of course the problem when you blow out "forecasts" is that you have to explain the next year why that won't happen again. The easy explanation is that the upside was due to "blue birds" - one-time customers who came in out of the blue and could not be forecasted. Because these upsides were out of the blue and one-time events, you can go back to your previous baseline, plus a couple percent, successfully sandbagging for another year.