I am genuinely surprised with Sri Lanka agreeing to tour Pakistan and am expecting appropriate security arrangements have been made to tackle the threats.
Pakistan would probably win this series even if the experienced Sri Lankan players were in the team which is why I am expecting Sri Lanka to lose this series, but they will definitely give them a tough fight. It will be interesting to watch how Pakistan perform after their World Cup journey.
When was the last time the terrorists attacked a sporting event in Pakistan? I am not very knowledgeable about the situation there, but I guess major cities are as safe as it could get. Obviously the Sri Lankans have reasons to be worried, as they were targeted during the last tour. But times have changed and the PCB has made better security arrangements this time.
It happened around in 2009. It has been 10 years now and I am quite sure that they have asked for good security arrangements before touring for the series.
I don't want to comment on terrorism in Pakistan but a terror attack can happen anywhere where from they can get public attention. They don't have to be in small or large cities.
Currently I find Pakistan in a better position in comparison to Sri Lankan team. Pakistan are full with good bowlers and experienced batsman while on other hand Sri Lankan team are quite out of form right now.