Train station Maarssen is such a marginal place that the entire OV-fiets check-out/in process has been automated.
My first block was at the key locker where after holding your OV-chipcard to the RFID point below, you have to enter your OV-fiets code (which is a barcode + number on the backside) and then your PIN.
I had forgotten my PIN, so an alternative option was provided to call a number where with an automated response after entering my OV-fiets code I was read out my PIN. Having obtained the PIN, I could then get a key (video of the reverse process of returning a key to the automated locker below).
After that the next step was getting through the dual human/bicycle gate. The bike has the be placed with its wheels in the cranny.
The RFID key chain has an automatic extension cord so you can touch it to the RFID point on this terminal. This terminal doubles as a payment point for people who store their own bikes in this storage area.
Then returning a similar procedure enables you to put your key back in the locker and nicely also indicate whether the bicycle is still in good order or not after which the locker flashes red and closes.
All in all a somewhat confusing but very doable process that felt like I was participating in an Alternate Reality Game (telephone numbers, secret codes, rush etc.).
Most people using OV-fiets currently are very well intentioned, but the systems look fairly foolproof and it remains to be seen how it holds up under wider exposure.