My thoughts are that if an SA feels like she has to make this point, the SA must feel that this behavior is pretty bad, and she is trying to prepare you for the possibility of disappointment. Your reason for the returns aside (with this many returns, I’m not sure that motives matter), I have heard premier luxury SAs at various brands comment, without mentioning names, that customers who multiple returns like this are more trouble than they are worth.* Post Covid, there are simply too many other clients who don’t have this issue.
Having said that, I think it’s unlikely that a client with large enough multiples, for example 5X, 10X etc., to be close to a QB really should be permanently impacted by something like a few pairs of sandals. Regardless of the honesty, I think that it’s a bit much for your SA to so bluntly state or imply or hint that such returns would adversely impact your chances of a QB. IMO only, I might not be comfortable shopping with such an SA bc every sale becomes a petty, transactional back and forth. JMO
ETA: you can ask to have the items transferred for you to try on in the store. SAs will do this for regular long-standing clients who they feel are serious about a purchase. In this time of relatively tight stock, it might require a bit more work for the SA and some horse trading, but it’s the best way if you are uncertain
* i am not expressing my own viewpoint here, but one I’ve heard from premier brand SAs.