Absolutely no problem. The 2 In/Out days are optional and flexible on how you use them, if you use them at all.

There is however a possible quirk/problem: the pass is not intended to do regular commutes (like same trip every day) for a longer period-ex: you live in FRA at the mo and go every day to KÓln-for whatever reason. DE=Germany and its DB will not like that. There are no clear rules and also no strict cut-offs for that-pass is meant for usual touristy purposes. I mention this as its DE that has been noted to make a fuss about this.

Although I fully agree that Interrailing is designed for touring, I have not seen any restrictions on how you actually use it, outside the max 2 days I/O and mandatory reservations.

If you were planning to use it for a daily commute, unless you live many Km from your workplace, I am sure local operators offer a wide range of commuter products considerably cheaper than an IR pass.

I am also surprised that operators keep any record of individual pass usage - certainly on my recent trip passes were checked but often not scanned, preferring to check reservation ticket codes.

Has anybody in the community any experience of retrospective feedback from Interrail on improper usage?

I am still using the pass fully for the touristic purposes, the only thing is that I travelled to Germany not using the pass but getting a separate ticket to get here and was hoping to start using a pass from now on to get to the rest of my trip destinations. 

Enjoy your trip.

Is reservation ticket code a seat reservation? It’s gonna be my first time using the pass and I am not sure what exactly should I reserve other than a seat on the train and adding a trip itself in the app. Is it something else I should reserve? 

Consider reservations as totally separate from your ticket to travel.

Assuming you have a mobile pass, to travel on any train with a Global pass you need your pass activated, a travel day created and the train you plan to travel on transferred from your trip.

You add trains to your trip either from the planner or  manually added - this is effectively your diary and nothing in there is a commitment to travel.

Once you create a travel day and add your planned train you can then press the See ticket tab and a QR code is generated that is valid for all trains you add to that travel day. - That is your ticket to travel.

Separately to that, some trains require mandatory or offer optional reservations. These are sourced from a range of providers and are listed elsewhere.

When you acquire your reservation you will receive a separate form of proof of the reservation from the agency used. It may be an e-ticket or a printed voucher. 

You will need this as a separate document/e-ticket along with your pass/ticket.

It is nowhere near as complex as it sounds, but please practice.

One last point - do not pre-activate your pass or add trains to your pass until you know you will be boarding. If you create a travel day in advance it can be deleted up to the previous day but not after midnight on the travel day.

If you want to check the operation of the pass you can always activate it, add a start date which automatically creates a travel day and add a train journey BUT be sure you remove them and deactivate your pass until needed.

Very enlightening information. Read slowly and with understanding. Regards