I figure that a 3.5 woman playing 8.0 mixed with a 4.5 man signed up to be a target (in league matches).
Pretty much. Unless both players have 0 experience in USTA, the 4.5 should at least be able to advise the 3.5 woman that she will be a target. Some of the good 8.0 teams here do play 3.5 women, but in terms of their net presence, they are not 3.5's at all. I've cranked multiple balls in a row at some of these 3.5 women (who play 8.0 mixed) and they manage to get them back. The avg. 3.5 adult league woman put in the same situation would have gotten beaned (probably) or flinched and not been able to make a play. I remember one match where I cranked 3 backhands in a row at the net woman from half way between the baseline and service box and she managed to volley the first two back, but framed the 3rd into the net. That's not normal for a regular 3.5 woman, haha.