If they were parking near your house in a place that you told them to park, of course you should. This would be your mistake.
However, if they parked there on their own idea, this would be their mistake. You offer your sympathy, and perhaps offer to contribute to paying part of the fines if you feel the need to, but paying for a parking ticket that wasn’t your fault would be insensible.
It depends on the area. I know when I moved to where I live now, I wasn’t yet aware of the fact that during a certain period of every weekday, there isn’t a single street within a mile radius where you can park without risk of getting a ticket. So if I’d invited a guest and they got a ticket because I wasn’t aware, yes, I would offer to pay it. However, if I knew and warned them and they got a ticket, they made the choice, so I wouldn’t offer.
My gf and I went out for a night on the town a few years ago. We returned to my car to find it had been towed as I had parked in some odd zone where between midnight and 3am, cars parked there would be towed. We went to the yard to get the car and first there was a fine for about $150 dollars for parking in that zone and then there was a $300 tow fee that had to be paid. I paid the $300. My gf took care of the $150. It helped.
If it was me who was driving, I’d make myself aware of where I was parking. If I got a fine, it’d be my responsibility. What were the circumstances that led to the ticket?
Absolutely NOT. Well, with one exception. If you told the person to park in the spot they got the ticket at and they were not familiar enough with the area to know they are going to get a ticket. In that case I would say at least offer to pay some. However, if you didn’t tell this friend is okay to park where they parked, it is their responsibility and theirs alone.
I suppose I would offer a BIT, but I’m just a generous spirit anyway. It’s truly the drivers issue unless as already said you guided them wrong and they had no idea. So who paid?