Depending on the jurisdiction, and local customs, operators of such booths ordinarily require a temporary food sales permit and government-issued licenses.

Discontinuous operators on complete spaces require a little more work.

Some operators require players to download free software to play their games.

In this context the operator requires a guide for action and not a scientific text-book.

Only in exceptionally cold circumstances will the operator require output overnight.

But the operator of such speakers requires a continuous supply of helium.

Sometimes the operator requires a dedicated, live printer - for example, when printing receipts for customers in real time, don't use spooling.

Dental operators require materials that are easy to manipulate and shape, where the chemistry of any reactions that need to occur are predictable or controllable.

All current operators require an 'Experimental' certificate to fly them.

Then the operators require payment on different grounds, and continuously harass, put under psychological stress and even threaten with legal action those who do not pay up.