Rather than utilize cross sales, change the ordering of the membership cost on the join form drop down to maximize profitability.
For example, if you have the following:
3 Day Trial (Recurring to Monthly)
7 Days - $7.97 (Recurring to Monthly)
30 Days - $39.95 (Recurring)
60 Days - $69.97 (Recurring)*
90 Days - $99.95 (Non Recurring)
Instead of listing them in that order, list the highest price point first, using a drop down menu, especially if it is a non-recurring option and even more so if you have the content that will retain that member past the 60 day option.
If you are able to and have the retention, add a higher period, higher priced recurring option too, you'll find that they will likely rebill at the end of 90+ days and just cancel instead of charging back.
Do some research into price points and the psychology of how pricing affects consumers then adjust and play with your price points on a regular basis to find out which one works best for your website, its content and your traffic sources.
Ultimately, what works for one person, may not work for another, A/B testing can be done relatively simply these days and you can gain a wealth of important information and consumer data from testing
IF you understand how to use that data to your advantage.
You'll find that you do end up with a couple of refunds using the method above
BUT, that is a better option than a pre-checked cross sale chargeback
That isn't to say there isn't a place for pre-checked sales, if they are done correctly, many companies (adult and non) use them on a daily basis and have no issues with them.