Would not normally cause a seal to blow.
If a trans is clean inside and in good condition, one may get away with fluid exchange without changing filter, but I have seen enough failures shortly after a fluid exhange or flush without changing filter afterward to advise against it. I do agree that keeping the fluid fresh and clean will add life to the trans, but alot of times the exchange or flush is done on a worn trans or one that has never been serviced, then the trouble begins. It is a good idea to know the trans' history.
James