Not much different from being on a tandem and not pushing on the pedals.
It's up to you whether you'd want to claim those particular tiles.
If it was me and those tiles were critical to my cluster/square then I'd probably plan on revisiting them with a solo effort just to make sure. They do seem a bit far away though, so they'd be right down on my list of priorities.
In reality you probably did some rowing in each of the tiles, and that's all that matters. How you get to a specific spot doesn't matter (I know I've got to the beginning of plenty of rides/runs using trains/cars/etc). It's not much different from people who record a short walk in an airport terminal in order to bag a specific otherwise tricky to get tile. I chose to ride various grim roads around the perimeter of Heathrow airport to back those tiles rather than just recording a short walk in the terminal building the next time I was there, but sometimes there isn't an easy alternative.
Does dipping just a few meters into a tile, often by foot, valid? Yes, so it's not much different from claiming it via a bit of rowing.
Bagging tiles with no human effort at all (like land sailing or riding a ferry) would be strictly out for me personally.
