To affect that many pools I think it must be a bug in stratum not MITM...
Surely though, if it were a bug in stratum, ALL pools would be affected. P2pool uses stratum but has no issues at all.
Peace.
Don't forget it would also affect all users if it was a bug in stratum. It's mostly the same users getting hit each time, and they are a very small subset.
EDIT: As Lucko posted, it hit his machines on 4 different pools, at 4 different locations on 2 different ISPs. That makes no sense that it would do that unless it's something specific to him. If the problem was pool side, or even widespread, you'd be seeing *massive* speed fluctuations on pools when these redirects happen. It isn't related to some clients not supporting it, since BTC Guild actually uses client.reconnect for it's public servers. EVERYBODY actively mining on the BTC Guild public stratum servers supports client.reconnect.