Ex divii and a mechanical trading system

[surfer]

Hi ,on a mechanical trading system,you need to follow the rules no matter what.Agree? Any ideas on how systems should treat a share that goes ex,Ie a large divi yield could cause a share to go down by 2%-3% on the day it goes ex which could mean that you get stopped out,hit a sell signal etc etc.Due to the fact you know normally on the Friday how much the share should go down(share should go down as the shareholders equity is decreasing when divi paid) .Any thoughts,ideas or experience on trading systems should treat for when shares go ex? Any changes to the system?