How to ride the Brussels Metro for free?
I'll admit I've rode a few times for free though never was it intentional. Once when visiting Brussels and arriving with only notes (bills) and realizing that the Metro kiosks don't take "swipe" U.S. credit cards, and having no change. Then most recently when my abonnement on my Mobib card expired at the end of the first month and not knowing I could buy a ticket from the driver. (Marius Renard does not have a kiosk.) I do have a valid monthly subscription currently, and compared to my monthly fuel cost in the U.S., I'll gladly pay it.
But in the course of our short discussion, I learned several of the European students don't even bother paying for their pass. Either they live on open Metro lines (no turnstiles) or make use of trams and buses. In fact I always see tons of people traveling without validating, so this just reinforced my my opinion that it occurs very frequently. This is even easier if you live close to your daily destination, mitigating the risk. Of course the risk is always there, but if you go two months without getting caught you're technically "making" money off the system considering a monthly pass is about 50 Euros.
Interestingly many of the students have yet to be hand-checked by agents yet, but me, traveling from Anderlecht to the VUB daily have had that opportunity a half-dozen times. Surely I would have been busted by now. Anderlecht is obviously one of the worse especially when a football game is going on at the stadium. Since I roll legit, (most of the time) I've yet to have a problem.
However in the case of trams, I rarely see them board the tram (once they did with dogs). You could of course, having seen the officers, remain on the vehicle to prevent from being caught. There's also another loop-hole if I understand right. If you have a valid ticket, but simply fail to validate it, then it's only a 10 Euro fine. So think about that! Carry a spare ticket (3.50 Euro) and you could go for months without getting caught. The moment you do, you show them the ticket, pay the 10 Euros and still come out on top. Sneaky!