The apps won't stop users from opening and editing documents or creating new ones. But unless you have the appropriate Office licenses for those users, they'll be breaking the license agreement if they do that for business documents.
These might include a license for an Office 365 tenant like E3, which includes the client software, an Office 365 Pro Plus license or Software Assurance in your Office volume license. It won't include the Office 365 Home Premium license users could buy (and try putting on their expense claim) from inside Office for iPad.
Microsoft solved that problem for Windows RT, which came with a touch version of Office Home and Student that didn't have commercial use rights, by including those use rights in Office 2013 volume licensing. And at the end of 2014, it introduced the Enterprise Cloud Suite, which includes Office 365 Enterprise E3, per-user Windows Enterprise SA subscriptions and the Enterprise Mobility Suite (Intune or System Center Configuration Manager client manage, Azure Rights Management Services for protecting shared documents and Azure Active Directory Premium, which gives you tools like single sign-on, two factor authentication and security reports), all in one agreement.
If you've mastered all that, prepare to prove it when you get audited. Alternatively, if you're prepared to get the ISO certification in software asset management, you can also get certified by BSA. The advantage of that is you'll get a two-year holiday from audits by BSA members. That's a laundry list of enterprise vendors, from Adobe, Apple and Autodesk to Microsoft and Symantec, so it would have kept Forever 21 out of court.
Sign up for CIO Asia eNewsletters.