At least they are telling you
BT Business Broadband don't even tell you if you are being capped.
If you exceed some mysterious figure a month on their unlimited service regardless of what you are actually using it for they restrict all your traffic and the throttling is terrible. Its actually worse than dial up speeds at the weekend and there is huge latency and it makes even simple browsing painful.
If they are going to cap then they should at least tell you when you are approaching the limit and then cap it a reasonable level without the high latencies.