Nope. They don’t look at traffic at all. It’s a smaller ISP, and they are apparently very afraid of net neutrality laws… they somehow think this means they can’t throttle at all other than to the paid-for bandwidth limit.
Yeah, that should be fine. If they’re identical on both sides they’ll be scanned and “synced” (no data will be transferred), if they differ you’ll get a conflict.
I’d like to confirm that I have the same/a very similar issue.
Sender: Xeon VPS, Ubuntu 14.04 Receiver: i7 Mac Mini and i5 MacBook Air
The files I’m trying to send are >1GB, I’ve tried both receivers separately over the past few days on three different Internet connections (16Mbit down/1MBit up, 6Mbit down/512k up, 50Mbit down/10Mbit up), the speed is nearly always the same (small second-long bursts up to the maximum of the link, on average somewhere in the 150-200kbit range).
To the best of my knowledge none of these providers throttle any kind of traffic. On all machines and all connections a simple rsync gives me the full performance.
As for resource usage: The server is bored to death with 7-9% CPU load on average and <500MB Memory usage, the receivers are usually somewhere in the 40-50% CPU usage and similar RAM category (±500MB). Mac Mini is a Fusion Drive, iostat giving me disk activity somewhere in the 20-30MB/s (it’s capable of >100MB/s), MB Air is heavily fluctuating between 5 and 40MB/s, but this can go a lot higher, as well.
Both receivers are sharing a folder with the server, as well, so there is upstream traffic in parallel, too. Would be nice to have a pause button per folder, btw. 
Any further feedback I can provide?
…there actually is one more thing I can provide: This only happens with big files, as I just found out accidentally.
Still waiting for my >1GB file to transfer, added another folder on the sender and started transferring to the receiver (MB Air, started from scratch). 3 minutes in, 260 files, combined 200MB have been transferred. At the same time my big file has gained about 5MB.
Both have v0.11.7