Well on one hand it would be wise to turn away a person who has poor equip ment because they will not ofer the full potential to ur group. And anyway if they have poor equipment they oviously do not know how to use there PP wisely.
However the quality of a player is not always determined by the equipment he/she has. They may not know how to buy their equipment properly but the may know wonders of how to group.
In conclusion i think it is right to turn someone away for what equipment they have because there are always othere people in the zone. Which you could invite instead of them.