(410 ILCS 82/45)
Sec. 45. Violations.
(a) A person, corporation, partnership, association or other entity who violates Section 15 of this Act shall be fined pursuant to this Section. Each day that a violation occurs is a separate violation.
(b) A person who smokes in an area where smoking is prohibited under Section 15 of this Act shall be fined in an amount that is $100 for a first offense and $250 for each subsequent offense. A person who owns, operates, or otherwise controls a public place or place of employment that violates Section 15 of this Act shall be fined (i) $250 for the first violation, (ii) $500 for the second violation within one year after the first violation, and (iii) $2,500 for each additional violation within one year after the first violation.
well, it appears they can fine you. I presume you fit within "a person that owns, operates, or otherwise controls..."
Not sure you will get any traction with the argument "but you didn't ticket the bartender and the patron (offender) and the statute clearly states "shall"". As with most situations, failure to cite others that are also violators generally is not a defense to your citation unless you can show some improper discrimination. It is likely the courts would simply say that the cite the person with the ultimate responsibility to control the situation.
as to needing a lawyer; if you were cited personally, I would think you could represent yourself. If the corporation was cited, then you would need a lawyer to represent the company.
Offhand, I don't see any defense on your part unless you want to argue that because of your absence, you did not have control and as such, are not liable for the violation. Of course, that would only be a possibility if it was you as a person cited and not the company. If you have rules in place against smoking and have the proper required signs posted, it might be worth a shot. That would mean that you took actions to enforce the rules and it was the bartender or manager on site at the time or even the corporation that should have been cited but not you.