Those who make regular trips to West Taiwan are unlikely to speak up lest they are spoken to the next time they enter the PRC. That is, if they were allowed entry.
Do I think there are people in the PRC willing to talk with Americans about this? Probably, but damn few and those would need separate confirmation before I believed them.
Were I visiting the PRC, I would go way out of my way to avoid talking with anyone about anything that the CCP might find upsetting. Because of my former work, the PRC is on the list of countries that I have to request permission to visit. I doubt it would be forthcoming.
I suspect that the people would be much more willing to talk to Chinese ex-Pats in Singapore of some such other country.
SpyNavy
Garde la Foi, mes amis! Nous nous sommes les sauveurs de la République! Maintenant et Toujours!
(Keep the Faith, my friends! We are the saviors of the Republic! Now and Forever!)
LonePalm, le Républicain du verre cassé (The Broken Glass Republican)