Lunch is often a difficult meal for many people as they struggle to find seating in a crowded restaurant, and even having a hostess does not always help. Some of the busier restaurants have learned to ask their patrons if they mind sharing a table, so this could be a way for two people in very different walks of life to meet. Each of them might have found they are alone, and their willingness to share a table could make lunch an interesting time. Those who find they enjoyed it can trade contact information that could take them far down the road to a relationship.
Chatting with friends is an expected part of eating lunch, but it can be difficult with a stranger. Both people will generally try to find common topics, but it will likely be awkward until the food arrives. Passing condiments is a good way to feel more comfortable, and they might even find it enjoyable when they realize they do not have to eat alone. What started off badly can turn into a relaxing meal.
For those unused to eating with strangers, it can be a time when they expand their own horizons. Those who have been in this situation many times will have found ways to cope with it, and they might have even made a few good friends that way. They will generally be the ones to introduce neutral topics of conversation, and their ability to feel comfortable in the situation should help the other person feel easier.
It is not easy to be in an unexpected social situation at any time, so being able to eat lunch with a stranger is something most people avoid. Those who have little or no social taboos might find it an interesting way to enjoy lunch while learning about the life of another person who could become their lifetime partner.