Would you let 2 horses run around the indoor arena together?

Okay so heres the deal, i started leasing a horse 2 weeks ago, my best friends own a horse at the same barn, with me so far? Over the past 2 weeks we've been riding together with the 2 horses, having races, we walk with them and graze together, and often in the arena when we were teaching them tricks (they were both free) they were walk over, say hi to the other horse and walk back over to do tricks again. They sound friendly towards each other right? Wednesday they were nibbling on each others necks and playing a little, then they decided to run, so we free lunged them together for a few minutes, sounded like a good plan to us... Everything went extremely well, they played, they ran then we went to get them and they were perfectly fine, same as always. Now we wouldn't of just thrown 2 horses together to make them run if we were not certain that they got to know each other a little, and were friendly towards each other, would you do it? At my old barn that was a normal thing to do, everyone did it, that's how horses met most of the time, and they were often free lunged together. but Tuckers owner got mad, apparently he is not to be free lunged with or without another horse ever. I understand it is her horse and obviously now that she told me i'm not going to do it again, but does she really have the right to get mad, when at the very beginning of the lease, i asked if there were any rules. She said there aren't any real rules besides me being the only one able to ride him. Its like she wanted us to guess the rules? I didn't see anything wrong with what we did, especially since she didn't say what i can or cannot do.... Just wondering your guys opinion on free lunging and horses meeting... Thanks