Legal Question in Real Estate Law in Illinois

Assuming that the use of your property has not changed, no.

Partly depends on how this arrangement was created, how long this arrangement has been going on, and whether it has always allowed for tenants to use it. Illinois has no "guaranty" of access like this so it is all a matter of "easements". Easements are rights of use that can be either "granted" or "prescriptive". Granted easements are actually agreed upon, and if your neighbor is giving you grief because the tenants are a problem, it may be a good time to write down the arrangements including repair and maintenance responsibilities, etc. If you ever sell your building it will help a buyer be clear on what the rights of use are. A "prescriptive" easement happens from continued use of someone else's property that is not objected to over time, but it can not "grow" meaning if it used to be for you alone and now you are letting tenants use it, that is a change that the owner of the driveway could object to. Again it may be time to set down arrangements in writing. Oral easements can become permanent after time but if the party whose property is being used (servient tenament) objects to the user (dominant tenament) it can result in friction, and potentially a lawsuit if things fall apart. The usual issue is who cares for the easement area (repair and maintenance) and proper insurance. And if the neighbor wants to sell having an easement affect (encumber) his property could be a problem for him if there are no written parameters.