Keep in mind that this is only dangerous for the attacker if the power they used has the entry that states "Target: All creatures in the burst/blast". If it says "enemies" or even a specific number (since you can always opt for *fewer* if a specific number is mentioned), swapping positions with the target wouldn't make them get hit by the power because, in the first case, they're not a legal target and, in the second case, they probably won't *choose* to target themself.