I honestly do not see any way you can guarantee this. The whole point in those meals is to do character meet & greets without lines. If they asked the server to ensure characters don't come over, I am not sure they could guarantee this, especially with CMs changing out. Additionally, you said they like to "see them at a distance", but the characters will go to the tables right next to their table, which could be several tables around them. In some restaurants, that is almost touching.
The CMs are good at reading the guests most of the time, but I still do not think they would totally avoid the table considering that is why people choose those particular dining locations.