Do you inform or comfront a guess that you think he or she is smoking in the hotel? Or do you send him an additional amount without informing he or she?

Tell the front desk and let them handle their guest.

I would politely let them know but also tell the front desk. The time you caught them is very unlikely the first time they have done it

I will inform them of the situation, and give them the hotel policy. I'll then let them know how sorry we are, but we will have to charge them what ever that amount is in the policy.

I will comfort them and let them know the policy that they have broken and charge them. Cause they could easily say it wasn't them.

I would never comfront a guest. Always take it through the front desk