We are currently attenuating sync in all Extron cables with a resistor and have been doing for some time.
HOWEVER - this resistor is likely redundant in console to BNC cables as extrons can accept any level of sync from 0.5vpp to 5vpp. What you have to worry about is the OUTPUT cable.
Many extrons have sync processing and the process amplifies the signal to 5VPP on output. Your input switches, if they have them will not affect this output.
These are the only extrons we know of so far that will take a 75 ohm signal and output that same 75 ohm signal without amplifying to TTL levels.
If your cables are unattenuated these extrons will still output TTL levels of sync. They are basically passthroughs. If you use unattenuated console cables or unattenuated sync stripper adaptors with these extrons OR with sync amplifying extrons, you still need an attenuated output cable if you are sending the signal to consumer grade technology like scalers and SCART TVs. But if your console cables are attenuated, your output cable for the above Extrons should NOT contain resistors. Otherwise there will be incompatibility with most devices and the signal will not work.
These extrons are also compatible with luma or composite video as sync, a nice bonus. TThey only have one output however, so the signals cannot be sent to multiple devices at once. There is a 4 switch and 6 switch in this range. If you only use 4-6 consoles in your setup, these devices work well.
If the wording in your extron's manual reads as following: "H output follows input" then it is outputting what it is given. It is also most likely compatible with luma and composite video sync, and we've confirmed this as we own one of the above Extrons.