Lots of strange hotmail users

Hello everybody,

Right now, there is a steady stream of new users coming onto 
myExperiment with hotmail addresses, normally which have no relationship 
to the user name. There are no obvious links in their details. Examples are:

"Marcwalton25" = hywulorthzjuena@...
"Clemglud24" = peparxikinsonmafarita@...

It looks extremely suspicious, but I can't figure out what they could be 
up to.

Alan