Maybe but if we're talking on the level of targeted government surveillance, I think all options are on the table, i.e. they should assume they are being watche

Maybe but if we're talking on the level of targeted government surveillance, I think all options are on the table, i.e. they should assume they are being watched everywhere they go, and that all their communications, including their close friends/family (or anyone they have already been talking to lately) are likely being monitored as well, in which case, getting a new phone may not do much of anything. Does that really not make sense?